[Observium] Problem with my Observium DB Error

Hi, i have some problems in the last days with my Observium. I have the subscription and for log time works fine. But in the last week have errors all time and my server are slow...

When this happen my apache give this error on the browser:

DB Error 1040: Too many connections

For this read in the FAQ need edit the /etc/mysql/my.cfg and set the max_connection=500 but nothing change.

or this another error:

DB Error 2013: Lost connection to MySQL server at 'sending authentication information', system error: 32

When execute the restart complete server works fine a few minutes and experiment the same errors and nothing works.

Any have any idea whats happen and the solution?

Thx BR Santiago