After upgrading from Ubuntu 22.04 to 22.10, Roundcube stopped working. Entering a username and password and clicking "login" redisplays the login page. No errors appear.
It didn't look like the database migrations ran, so I tried running them manually. Got some DB errors (columns/indexes failed to be added removed), so I deleted the database and created a new one with the current schema. Still seeing the same failure.
In config.inc.php, I enabled $config['imap_debug'] = true; and $config['sql_debug'] = true;. I am not seeing any IMAP logs and nothing interesting in the SQL log.
How can I further debug this?
Solve: PHP's post_max_size was too small.