Unexpected error with no real details given

[RandyPgh]

On one of our reports that uses a live Enterprise Gateway connection, the result is a page of errors. When I click any of the Details links, I get the below description.

Activity ID    846ac52c-5a96-4a2e-9be4-ab1e6a2f462f

Time    Fri Apr 22 2016 16:23:41 GMT+0000 (Coordinated Universal Time)

Version   13.0.1100.351

Cluster URI    https://wabi-us-north-central-redirect.analysis.windows.net

Another report in the same workspace and using the same EG connection works fine.

Thanks for any assistance.

[RandyPgh · Accepted solution]

Fixed. I was missing the banner added to the top which said that the EG connection was not established.