1. Inadequate preparation of materials: The application for extending the principal of the student-origin student loan needs to provide necessary materials, including proof of family economic status, employment certificate, repayment plan, etc.

2. There is an error message in the loan extension statement: the contents in the loan extension statement are inconsistent with the actual situation. Once it is found out by the bank, the application for loan extension will be rejected, resulting in the failure of the application for student loan extension.