Grafana + Prometheus


I use docker-compose and all looks good, I can log in and see everything grafana and prometheus
but the two cannot communicate.
In the datasource for prometheus I get a
“HTTP Error Bad Request” message (without further detail)
error when pressing save&test and

in the dashboard all graphs has an error:
“invalid parameter ‘start’: cannot parse “” to a valid timestamp”

In the explorer I get
“invalid parameter ‘query’: 1:1: parse error: no expression found in input”
for whatever query.

How can I debug what could be wrong?

This in the CLI e.g. return a result that looks normal:
curl ‘

Grafana v6.7.2 (423a25fc32)
Prometheus: v2.17.1


Not sure why/how it is related. But in my case it was the trickster which caused the problem. Once I directed the datasource directly to the prometheus. It seems to solve the problem

Getting the same issue.
Have you solved it?