Could not find datasource Data source not found for Graphite

Hello Experts,
We have been seeing this error intermittently in our grafana logs.

t=2018-03-15T17:10:10+0000 lvl=eror msg=“Alert Rule Result Error” logger=alerting.evalHandler ruleId=1205 name=“Data Science Hadoop-F Hive Table Sizes alert” error=“Could not find datasource Data source not found” changing state to=keep_state.

The datasource in question is datasource to graphite. Any light on this ??