Openvas with PostgresSQL Could not authenticate to manager daemon

Hi all,
actually we have a 10 core VM with 30GB RAM and a Openvas (openvas9-manager_7.0.3-2) built with a local PostgresSQL database.
On the system we actually have quite 700 IPs and 20 daily scans.

Using openvas web GUI we often get an error:

Internal error: exec_omp_get:3113 (GSA 7.0.3)

An internal error occurred. Diagnostics: Could not authenticate to manager daemon.

Querying the database via psql, the database seems answer correctly
I had the same problem with Openvas and SQlite and the problem was the SQlite timeout.
Is the a param to set timeout for Postgres?
Any idea about solving the problem?

Thank you all