If you don't have a large database then go to 'Database -> Database Management'. Click the 'Housekeeping' button and run the following in this order:
1. Tune PostgreSQL (this only needs to be completed once ever. If this step fails, you can safely skip to step #2)
2. Reindex
3. Cluster
4. Vacuum/Analyze
After the housekeeping is complete rebuild the database cache via 'Rebuild Cache -> Full Cache Rebuild'.
If that doesn't resolve the problem please send your support bundle to us via a
Support Ticket instead of attaching it here on the forum.