Does TestFlight have restrictions for how often you can upload .ipa files to its API?
The reason I ask is because I am uploading via a .sh script and it works sporadically.
It would be best to ask them directly, but from my experience I have never had an upload rejected except when their service is acting up.
I have used the TestFlight Jenkins plugin which uploads every successful build.
Their documentation also does not suggest there are any limits, https://testflightapp.com/api/doc/