To use this application, you must first sign in to iTunes Connect and sign the relevant contracts

Cing Sian Dal

Aug 3, 2018·1 min read

1. Open Xcode.
2. Login again.
3. Quit Application Loader if opening and Xcode.
4. Open Application Loader via Xcode.
5. Login the account inside Application Loader.
6. Worked.

The error happened to me when the account password has changed.