Grafana TLS handshake error

Hello everyone,

we use icingaweb2, influxdb2 and grafana on the same host.
The Grafana module with iFrame works, but I want to use the Image Renderer.
Here I have the problem that the image is generated correctly
/var/lib/grafana/png/ but it doesn’t show up in Icinga.

I didn’t find any errors in any log except the syslog:
icingatest grafana[108744]: server.go:3214: http: TLS handshake error from remote error: tls: unknown certificate

Thanks for your help!

Does your Grafana use/enforce TLS?