This also happened to me today. I’m on Nextcloud 11.0.0.10 and tried to hide a lot of fatal log entries in my admin log page by un-ticking the checkbox for fatal log entries. After that nothing loaded on the log page just as flowlee stated above.
I’m not that experienced with mysql database manipulation so it took me some time to modify the code above to work for me. I logged in to mysql and loaded my nextcloud database. Then I checked the value of the specified row to try my command:
mysql> SELECT * from oc_appconfig WHERE appid='logreader' AND configkey='levels';
+-----------+-----------+-------------+
| appid | configkey | configvalue |
+-----------+-----------+-------------+
| logreader | levels | 11110 |
+-----------+-----------+-------------+
and then updated the value:
mysql> UPDATE oc_appconfig SET configvalue='11111' WHERE appid='logreader' AND configkey='levels';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
That solved it for me. Thanks for pointing me to the right row!
This is the related issue on github: https://github.com/nextcloud/logreader/issues/35