Grafana graphs show 504 / 502 while calling prometheus data source


Grafana gets 504/502 while using prometheus data source while running the same query using curl gives back an answer i. following works :

curl -v -L -u : ‘http://<prom_server>/api/v1/query_range?query=avg(rate(http_get_title_timer_sum%7Bstack%3D%22search-service–2001-3-442–76GrqRw%22%7D%5B2m%5D)%20%2F%20rate(http_get_title_timer_count%7Bstack%3D%22search-service–2001-3-442–76GrqRw%22%7D%5B2m%5D))*1000&start=1498679590&end=1498681390&step=1’

Any ideas on how to debug if there is a grafana issue?

Any errors in the console in your browser or in the Grafana server logs?