Self-hosted Snikket troubleshooting

Problems with your Snikket setup? Don’t worry! Most people don’t experience any issues, but if you do, it’s likely something simple. This page describes problems you might encounter, and how to solve them.

General problems

“Snikket is starting” page does not go away

If this page stays for more than a few minutes, there was probably an issue obtaining certificates for your Snikket service. For more information on diagnosing certificate issues, see the ‘Certificates’ section later on this page.

Unable to share large files

If you find that your users cannot share large files through Snikket, there could be a couple of reasons:

  • If you are using Snikket behind a reverse proxy, ensure that the proxy does not place a limit on the size of uploads. Check our reverse proxy guide for more information.
  • If the file is over 100MB, Snikket will attempt a direct device-to-device transfer. This requires you and your recipient to be online at the same time, and it only works between two users (not in groups). Also note that direct transfers are not currently supported to or from iOS devices.
  • To share files over 100MB with a Snikket group or iOS users, we recommend a dedicated file transfer service. You can find a list of standalone self-hosted file transfer services, use a system such as NextCloud, or select one of the many free online file transfer services.

Invitations are always expired

If all invitation links show as expired immediately after you create them:

  • Check you copied the entire URL correctly.
  • Ensure that you don’t have an XMPP server or other service running on the same system as Snikket using port 5280.
  • If you use a reverse proxy, check that it is correctly forwarding requests to Snikket. See our reverse proxy guide for more info.

Not responsible for this domain

If you see an error in the app reporting that the server is “not responsible for this domain”:

  • Check that you do not have another XMPP server running on the same system as Snikket. It may be using the ports that Snikket needs.
  • Check that your DNS setup is correct, and you do not have SRV records left over from a previous XMPP installation on the same domain. If you recently modified your DNS records, you may need to wait a while for DNS caches to expire the old records.

Host compatibility

Although Docker mostly isolates Snikket from the host system that you install it on, it does depend on certain capabilities of the host. This section lists any known compatibility issues.

Docker version compatibility

Certain old versions of Docker are incompatible with Snikket releases from January 2024 and later. We recommend ensuring that you have Docker 20.10.10 or later installed on the host system. Otherwise, you might see that Snikket has trouble starting, obtaining certificates or other functionality may not work.

Problems on Debian/Raspbian 10 (“buster”) on Raspberry Pi or ARM devices

If you use Debian or Raspbian version 10 (“buster”) on a Raspberry Pi or other ARM-based system, you may experience Snikket’s containers failing to start with errors such as "Operation Not Permitted" or "init_interp_main: can't initialize time".


Docker uses a system library called libseccomp2 to isolate the main system from the containers. The version of that system library shipped with Raspbian Buster by default cannot handle certain time-related operations and it unfortunately returns an error code which confuses the things attempting to use it.


There are two options to fix this:

  • You can upgrade your system to Raspbian (or Debian) 11 (“bullseye”). This will ship with a newer libseccomp2 by default which does not have that issue.

  • Alternatively, you can install an updated libseccomp2 package from backports without upgrading your entire system. To do so, run:

    apt-get install libseccomp2/buster-backports

    If that command prints E: Release 'buster-backports' for 'libseccomp2' was not found or similar, you need to enable backports first. To do so, follow the Instructions on the Debian Backports page up to and including “Add Backports to sources.list”. Make sure to enter “buster-backports” and not “bullseye-backports” into your sources.list!

    Now, you should be able to run the above command with success. You may have to restart the docker daemon or the containers after this, using:

    systemctl restart docker
    docker-compose up -d  # <- run this in your snikket directory

Certificate problems

Certificates are an important part of securing connections to your Snikket.

Snikket automatically obtains certificates from Let’s Encrypt, and keeps them up to date. This usually works without problems, but it can be sensitive to a number of things that might cause it to fail.

Common causes

Common causes of an inability to obtain or renew certificates:

Missing or incorrect DNS records

Snikket needs 3 DNS records to be added. Ensure you followed the steps from the installation guide correctly, particularly the DNS configuration.

If your server supports IPv6, you may also add that to DNS (using an AAAA record).

Port 80 blocked

Ensure that port 80 is open and accessible. You can review a list of ports required by Snikket. Port 80 is required to be open by Let’s Encrypt so they can verify your domain.

On a VPS or in a cloud environment, your provider may require you to manually open ports, e.g. in their web dashboard. If you are running in a LAN, you may need to forward ports in your router’s web interface.

Finally, check the firewall on the server itself (e.g. ufw, iptables or nftables).

Incorrect reverse proxy configuration

If you have a reverse proxy set up (e.g. to run Snikket on the same server as other websites or services), it needs to correctly forward requests to Snikket on both http and https.

See our Snikket reverse proxy documentation for more information on correctly configuring reverse proxies.

IPv6-only network

If your Snikket instance is on an IPv6-only network, ensure you are using the latest docker-compose.yml. Specifically, there should be a network_mode: host under the snikket_certs: line.

Incompatible Docker version

Certain old versions of Docker prevent Snikket from starting properly. Ensure you have Docker 20.10.10 or later.

Certificate debugging commands

Checking for errors

If you think you have everything set up correctly and you’re not sure what the problem could be, check the error log:

cd /etc/snikket
docker-compose exec snikket_certs cat /var/log/letsencrypt/errors.log

If you get a “No such file or directory” error when running the above command, inspect the debug log instead:

cd /etc/snikket
docker-compose exec snikket_certs cat /var/log/letsencrypt/letsencrypt.log | grep detail

Trying again

Once you have fixed any problems, you can force a new attempt with the following command:

cd /etc/snikket
docker-compose exec snikket_certs /etc/cron.daily/certbot

If that command says that no certificates are due for renewal, but you need to trigger a renewal anyway, run:

cd /etc/snikket
docker-compose exec snikket_certs su letsencrypt -- -c "certbot renew --config-dir /snikket/letsencrypt --cert-path /etc/ssl/certbot --force-renew"

Note that Let’s Encrypt has strict rate limits - do not run these commands more often than necessary, or you may find yourself unable to get new certificates for a while.