Grafana doesn't recognize private ip only

Hey, I have grafana and I’m setting new datasource as influxdb; but for some reason I get
Network Error: Forbidden(403) - Red Error at the bottom of page when trying to save
When I set datasource as my private IP 10.x.x.x it gives the error but when - all is fine, anyone have idea why? Cause of that I can’t connect to other instance datasource ( also influx )

PS: I have exactly same thing on stg env - but for some reason can’t replicate here.

On stg is working tho.