Sporadic 500 errors with no reason

Dear grafana/influxdb users,

since last upgrades:

  • grafana: 6.2.0
  • influxdb: 1.7.6-1

I have sporadic internal server errors on different dashboards. The only log I have is:

t=2019-06-05T11:05:23+0200 lvl=eror msg="Request Completed" logger=context userId=52 orgId=2 uname=manu method=POST path=/api/datasources/proxy/1/query status=500 remote_addr=x.x.x.x time_ms=27 size=1723 referer="https:/fqdn/d/7O5msiZZz/s-m-a-r-t?orgId=2"

no more erros in grafana log or influxdb :frowning:
Any idea to identify the root cause?