Unable to publish iOS app to beta external groups in testflight

Hi Team - we are publishing an app from Azure pipelines and receiving an error "Error: 'What to Test?' is required when using 'Distribute to External Testers'."

I have tried providing a file name at GitHub "releaseNotes.txt" and the raw data. nothing worked out.

Please help me with this. what needs to be configured in the release notes option?

Unable to publish iOS app to beta external groups in testflight
 
 
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