Try removing "epoapp" from the Database Instance field in the ePO config, leaving it blank.
Does your ePO database allow SQL authentication? The "Test Connection" for the database is incredibly misleading as it doesn't actually work.
If you watch your SQL logs when you do a test connection you'll see the source of the request as your ePO server but if you force a manual refresh (under Device Management), you'll see that the authentication attempt comes from the associated receiver, not the ePO server.
In our environment we created a local SQL account and enabled SQL authentication (don't forget to restart the SQL instance), and everything has worked without issue since.
Database name should be typed as:
- with [ ] brackets
can ypu help me this case?
if you have tried the Artek suggestion please let us know.
Also check the SQL/windows logs for some messages as with that version and 9.3.2 there are some issues related to the authentication mechanism based on the windows security policy (LM,NTLM, NTLMv2) but with SQL authentication all should be okay(Try with different user with permissions over the ePO db).
Check /var/log/messages for something more speciefic.