[Observium] SQL query instead of port detail

hi.

I just installed another instance ob observium. While my first one is working like a charm (installed 6 weeks ago) this one has a strange behaviour.

For example: When I click on a device and then click on the showed graph I do net get the port details with more detailed RRD graph (where you can changes the range with time and date). Instead only a SQL query is showed :(

Any ideas what causes the issue?

best, Wolfgang