People are experiencing issues with TestFlight recently, builds are not getting to devices.
Looks like it happens if you need to provide export compliance information on encryption.
However it turns out you can set an Info.plist key to indicate your export compliance in the app itself and you won’t need to answer these questions each time you upload a build.
Indicate that the app is exempt from the export compliance.
<key>ITSAppUsesNonExemptEncryption</key>
<false/>