A cell in a notebook that is using the %run magic command to run another notebook was running for what I considered too long and so I clicked the interrupt button and now the button is greyed out and giving a spinning circle.

The interrupt button at the top of the notebook doesn't do anything either.

Screenshot attached.

I saw a similar post here but the issue resolved itself. 

https://community.databricks.com/t5/data-engineering/hanging-frozen-cancelling-running-cells-in-note...