Uppgrade problens 7.10.10 to 7.11.6 and 7.11.7

I have problem upgrading from 7.10.10 to 7.11.6 or 7.11.7
7.11.6 or 7.11.7 give same problem: users cant log in.

[FATAL] Error: Query limit or 20000 reached for Home modul

I have red the forums about increasing default_limit in config but should not 20000 be OK??
It looks like a memory leek or similar, the system are very slow.

Installed on VPS with CentOS 7
Suggestions please?