Different problems that can occur on a new instance, and how to solve them.

Many Lemmy features depend on a correct reverse proxy configuration. Make sure yours is equivalent to our nginx config.



For frontend issues, check the browser console for any error messages.

For server logs, run docker-compose logs -f lemmy in your installation folder. You can also do docker-compose logs -f lemmy lemmy-ui pictrs to get logs from different services.

If that doesn't give enough info, try changing the line RUST_LOG=error in docker-compose.yml to RUST_LOG=info or RUST_LOG=verbose, then do docker-compose restart lemmy.

Creating admin user doesn't work

Make sure that websocket is working correctly, by checking the browser console for errors. In nginx, the following headers are important for this:

proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";

Rate limit error when many users access the site

Check that the headers X-Real-IP and X-Forwarded-For are sent to Lemmy by the reverse proxy. Otherwise, it will count all actions towards the rate limit of the reverse proxy's IP. In nginx it should look like this:

proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;


Other instances can't fetch local objects (community, post, etc)

Your reverse proxy (eg nginx) needs to forward requests with header Accept: application/activity+json to the backend. This is handled by the following lines:

set $proxpass "{{ lemmy_ui_port }}";
if ($http_accept = "application/activity+json") {
set $proxpass "{{ lemmy_port }}";
if ($http_accept = "application/ld+json; profile=\"\"") {
set $proxpass "{{ lemmy_port }}";
proxy_pass $proxpass;

You can test that it works correctly by running the following commands, all of them should return valid JSON:

curl -H "Accept: application/activity+json"
curl -H "Accept: application/activity+json"
curl -H "Accept: application/activity+json" # the id of a local post
curl -H "Accept: application/activity+json" # the id of a local comment

Fetching remote objects works, but posting/commenting in remote communities fails

Check that federation is allowed on both instances.

Also ensure that the time is accurately set on your server. Activities are signed with a timestamp, and will be discarded if it is off by more than 10 seconds.

Other instances don't receive actions reliably

Lemmy uses a queue to send out activities. The size of this queue is specified by the config value federation.worker_count. Very large instances might need to increase this value. Search the logs for "Activity queue stats", if it is consistently larger than the worker_count (default: 64), the count needs to be increased.