Because this affects every app and no agreement is pending, it sounds account-side rather than build-specific. Have the Account Holder check App Store Connect → Business → Agreements, Tax, and Banking. If nothing is available to accept, update your existing Support case with the Team ID, exact error, timestamps, and ask Apple to verify the TestFlight Beta contract is attached to the team and re-provision it if needed. There may be no self-service fix when the contract is missing from the account.
Topic:
App Store Distribution & Marketing
SubTopic:
TestFlight