Initially we tried to setup Bigquery source for import but we are blocked by an issue for which my colleague Aman has asked a question here: 

As an alternative method, I am trying to use GCS as the source. I have completed all the steps mentioned here: https://www.docs.developers.amplitude.com/data/sources/google-cloud-storage/
In the Edit Import Config section, I am seeing correct sample data in Select File step
 

 and also after Configure Converter

When I click on “Save & Enable Source”, I also get a feedback saying that 

“Successfully update converter” and “Source enabled”

But after this, when I go to Events, I am not able to see any events from this source.

When I go to General tab of the GCS source, status shows up as Disconnected
 

and the Ingestion Jobs tab shows this:
 

Not sure what the issue is here because in the sample data shown while editing the converter config, everything seems to work fine