The exact fix for us using Docker:
- Run
docker exec -it <postgres-container> "bash"
to connect to your postgres database container. - Run
psql -U lemmy
to connect to the database with the lemmy user. - Run
update site set icon = null where id = 1;
then\q
then exit
By randommouse on Github](https://github.com/LemmyNet/lemmy-ui/issues/1530#issuecomment-1605781461)