Taskserver Troubleshooting

Searching for failures with your Taskserver setup.

Troubleshooting Sync

Sync Problems

Here is a list of problems you may encounter, with the most common ones listed first.

The single most common problem has been that the Taskserver Setup Instructions were not properly followed. Please review the steps you took.


It is always a good idea to make sure that you are using the latest release of Taskwarrior and Taskserver, not just because bugs are fixed that may help you, but also because the solutions below are geared toward the current releases.

If you upgrade from an older release of Taskserver, you will need to follow the upgrade instructions.

'task sync' showed task list

You have a version of Taskwarrior older than 2.3.0, which means there was no sync command, and you are seeing a list filtered by the search term 'sync'. Upgrading is the only solution.

Taskwarrior without GnuTLS

You are using version 2.3.0 or later, but the Taskwarrior binary was compiled without GnuTLS support.

If you installed Taskwarrior using your OS's package manager, you may be suffering from an out of date package. Prod your OS's package maintainer for an update.

GnuTLS and recent releases

Recent releases make GnuTLS support opt-out instead of opt-in, so upgrading to the latest version may help. Otherwise, you will need to build Taskwarrior from the latest source tarball, following the instructions in the INSTALL file. If you are a developer, do that. If you are not, then installing a development environment is probably not something you want to do, in which case contact your OS's package maintainer.

Verify GnuTLS support

Verify that your Taskwarrior was built with GnuTLS support by running task diagnostics:

        $ task diagnostics | grep libgnutls
        libgnutls: 3.3.18

nodename nor servname provided

This means the Taskwarrior setting taskd.server=<host>:<port> refers to a host name that cannot be seen by Taskwarrior.

  • Is it spelled correctly?
  • Is the domain correct?
  • Is there a valid DNS resolution for the name?
  • Is there a firewall between Taskwarrior and Taskserver that is not letting through <port> traffic?

Could not connect

Taskserver may not be running on <host>.

Check with ps -leaf | grep taskd.

Sometimes the error message is misleading, please check "Handshake failed" as well.

Unable to use port

By default, port 53589 is used, but whichever you chose must be open on the server.

If you are unable to open firewall ports, you can use an SSH Tunnel to route port 53589 traffic over port 22:

        $ ssh -L localport:dsthost:dstport user@example.com

Handshake failed

There are many reasons that the TLS handshake can fail.

Please do the following on your client:

        $ openssl s_client -CAfile .task/ca.cert.pem -host HOST -port PORT

The result should be something like Verify return code: 0 (ok).

Handshake errors

  • Certificate fails validation, Handshake failed
  • Could not connect to <host> <port>

When you generated certificates, you modified a vars file, in particular the CN=<name> setting. That name must match the output of hostname -f on the server for the certificate to validate.

        $ certtool -i < server.cert.pem | grep Subject:

        $ openssl x509 -noout -in server.cert.pem -subject


Additionally, that name must also be used in the taskd.server=<host>:<port> setting for Taskwarrior. Otherwise you'll need taskd.trust=ignore hostname.

If you are using a self-signed certificate, did you specify it using the taskd.ca setting?


Setting taskd.ciphers can force the use of different ciphers. Use gnutls-cli --list to see a list of installed ciphers, and confirm that there is overlap between client and server. There needs to be a cipher that is available to both, otherwise they cannot communicate.

Certificate still valid?

Certificates have expiration dates, and if you followed our instructions, you created a certificate that is valid for one year. Check your certificate with this command:

        $ certtool -i --infile ~/.task/<YOUR NAME>.cert.pem

If your certificate has expired, you need a new one. You may also need to regenerate expired server certificates.

Note on validation dates

Note that creating certificates that never expire is a bad idea. Certificates may be compromised. A certificate that is considered secure today, may not be considered secure in a year. Is the key length you chose something that will remain suitable in the future? Will the algorithms you chose remain secure? For these reasons, choose an expiration date that lets you reevaluate your choices in the relatively near future.

Note on GnuTLS security

As a security product, it is imperative that you keep your GnuTLS up to date.

As with many security products, GnuTLS is maintained by a responsible and quick-responding team that takes security very seriously. Benefit from their diligence by keeping your GnuTLS up to date.

GnuTLS outdated?

We have received reports of issues with older GnuTLS releases. Specifically, version 2.12.20 has problems validating certificates under certain conditions. Newer releases have addressed memory leaks that were able to take down Taskserver.

Please keep in mind that you have to recompile Taskserver completely to benefit from the new version.

Recompile Taskserver

Upgrading GnuTLS does nothing to upgrade taskd -- it has to be rebuilt from scratch, which means:

        $ cd taskd.git
        $ rm CMakeCache.txt
        $ cmake -DCMAKE_BUILD_TYPE=release .
        $ make
        $ sudo make install

This can then be verified using taskd diagnostics.

Ancestor not found

You skipped the important step of running:

        $ task sync init

This performs an initial upload of your tasks, and sets up a local sync key, which identifies the last sync transaction.

Please note that older Taskwarrior versions (before 2.5.1) only sync the pending tasks and not all tasks.


Hostname and IP address

There is a difference between hostname and IP address, honestly. We are referencing the hostname throughout the documentation because you need a valid hostname for the certificate and working name resolution for the client to connect to the server.

So please use the hostname where you are advised to do it!


You may wish to try and debug the problem yourself. You will probably not. But if you do, here is how.

Both Taskwarrior and Taskserver have a diagnostics command, the purpose of which is to show you relevant troubleshooting details. Additionally it will indicate problems directly, for example, it will tell you if your cert/key files are not readable. The output from diagnostics is intended to be included in bug reports, and doing so saves you a lot of time, because it's the first thing we'll ask for.

task diagnostics

        $ task diagnostics
        $ taskd diagnostics
Read the output of the diagnostics commands carefully, there may be several types of problems mentioned, which need to be addressed before going further.

Taskserver Debug Mode

The next step would be to run the server in debug mode. First shutdown your Taskserver, then launch it interactively:

        $ taskdctl stop
        $ taskd server

You can hit Ctrl-C to stop this server. For highly verbose output, try this:

        $ taskd server --debug --debug.tls=2

Taskwarrior Debug Mode

Similarly, Taskwarrior has a verbose debug mode, and debug TLS mode:

        $ task rc.debug=1 rc.debug.tls=2 sync


Server tools

IP Address

Show the IP addresses (and network interfaces) on the system.

        $ ifconfig -a
        eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet netmask broadcast
        ether 52:54:a2:01:25:9d txqueuelen 1000 (Ethernet)
        RX packets 42091 bytes 46300226 (44.1 MiB)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 17689 bytes 2606921 (2.4 MiB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

        lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
        inet netmask
        loop txqueuelen 0 (Local Loopback)
        RX packets 120 bytes 43540 (42.5 KiB)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 120 bytes 43540 (42.5 KiB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

        $ ip addr list
        1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet scope host lo
        valid_lft forever preferred_lft forever
        2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 52:54:a2:01:25:9d brd ff:ff:ff:ff:ff:ff
        inet brd scope global eth0
        valid_lft forever preferred_lft forever


Shows which process listen on the port, shows the user and – more important – the IP address / interface the server runs on.

        $ lsof -i TCP:53589 -s TCP:LISTEN # as taskserver user or with sudo
        taskd 1167 taskserver 4u IPv4 16682 0t0 TCP taskd.example.net:53589 (LISTEN)

        $ netstat -tl | grep 53589
        tcp 0 0 taskd.example.net:53589* LISTEN


Shows the hostname from "General Reachability" (Client section) after CN=

        $ openssl x509 -noout -in server.cert.pem -subject
        subject= /CN=taskd.example.net/O=My own IT

        $ certtool -i --infile=server.cert.pem | grep Subject:
        Subject: CN=taskd.example.net,O=My own IT

taskd diagnostics

Shows server diagnostic data.

        $ taskd diagnostics --data /path/to/taskserver/data/

        taskd 1.2.0
        Platform: Linux
        Hostname: taskd.example.net


        Build Features

        TASKDDATA: /path/to/taskserver/data
        root: /path/to/taskserver/data/, readable, writable
        config: /path/to/taskserver/data//config, readable, writable546 bytes
        CA: /path/to/taskserver/data/ca.cert.pem, readable, 2017 bytes
        Certificate: /path/to/taskserver/data/server.cert.pem, readable, 2004 bytes
        Key: /path/to/taskserver/data/server.key.pem, readable, 10996 bytes
        CRL: /path/to/taskserver/data/server.crl.pem, readable, 1080 bytes
        Log: /path/to/taskserver/data/taskd.log (found)
        PID File: /path/to/taskserver/data/taskd.pid (missing)
        Server: taskd.example.net:53589
        Max Request: 1048576 bytes
        Trust: strict

Client Tools

General Reachability

Show if the hostname is reachable (if ping is not blocked).

        $ ping taskd.example.net
        PING taskd.example.net ( 56(84) bytes of data.
        64 bytes from taskd.example.net ( icmp_seq=1 ttl=64 time=0.118 ms
        64 bytes from taskd.example.net ( icmp_seq=2 ttl=64 time=0.066 ms
        64 bytes from taskd.example.net ( icmp_seq=3 ttl=64 time=0.064 ms
        64 bytes from taskd.example.net ( icmp_seq=4 ttl=64 time=0.065 ms
        --- taskd.example.net ping statistics ---
        4 packets transmitted, 4 received, 0% packet loss, time 3000ms
        rtt min/avg/max/mdev = 0.064/0.078/0.118/0.023 ms

        $ nmap -sP taskd.example.net

        Starting Nmap 6.40 ( http://nmap.org ) at 2016-05-15 11:24 CEST
        Nmap scan report for taskd.example.net (
        Host is up (0.00012s latency).
        Nmap done: 1 IP address (1 host up) scanned in 0.01 seconds

Port Reachability

Shows if the port is reachable by client (or locally).

        $ telnet taskd.example.net 53589
        Connected to taskd.example.net.
        Escape character is '^]'.
        ^CConnection closed by foreign host.

        $ sudo nmap -p 53589 taskd.example.net

        Starting Nmap 7.12 ( https://nmap.org ) at 2016-05-15 11:28 CEST
        Nmap scan report for taskd.example.net (
        Host is up (0.036s latency).
        53589/tcp open unknown

        Nmap done: 1 IP address (1 host up) scanned in 0.18 seconds

        $ openssl s_client -host taskd.example.net -port 53589

Hostname resolution

Shows the ip address of hostname. Should match one of the IP addresses found in "IP Address" (Server section) and the server should be bound to that address see "Ports" (Server Section).

        $ host taskd.example.net
        taskd.example.net has address

        $ nslookup taskd.example.net # checks only nameservers

        Non-authoritative answer:
        Name: taskd.example.net

task diagnostics

Shows client diagnostic data.

        task diagnostics

        task 2.6.0
        Platform: Linux
        Build Features
        File: /home/user/.taskrc (found), 2428 bytes, mode 100664
        Data: /home/user/.task (found), dir, mode 40775
        Locking: Enabled
        GC: Enabled
        $EDITOR: vim
        Server: taskd.example.net:53589
        CA: ~/.task/ca.cert.pem, readable, 3741 bytes
        Trust: strict
        Certificate: ~/.task/Dirk_Deimeke.cert.pem, readable, 3724 bytes
        Key: ~/.task/Dirk_Deimeke.key.pem, readable, 25364 bytes
        Ciphers: NORMAL
        Creds: My own IT/Dirk Deimeke/************************************



Getting Help

Getting Help

As a last resort, ask for help. But please make sure you have carefully reviewed your setup, and gone through the checks above before asking. No one wants to lead you through the steps above to discover that you didn't.

We'll ask you to provide the diagnostics output for both Taskwarrior and Taskserver, then we're going to go through the steps above, because this is our checklist also.

Getting Help (1)

There are several ways of getting help:

  • We have an FAQ covering a lot of questions.
  • Email us at support@taskwarrior.org, then wait patiently for a volunteer to respond.
  • Join us IRC in the #taskwarrior channel on Freenode.net, and get a quick response from the community, where, as you have anticipated, we will walk you through the checklist above.

Getting Help (2)

There are several ways of getting help:

  • Even though Twitter is no means of support, you can get in touch with @taskwarrior.
  • We have a User Mailinglist which you can join anytime to discuss about Taskwarrior and techniques.
  • The Developer Mailinglist is focussing on a more technical oriented audience.