https://help.tallysolutions.com/docs/te9rel64/Error_warning_message/TSS.htm

TSS - Error Messages

This topic lists commonly appearing TSS-related error messages.

1. To complete this action internet connectivity is required. Connect to internet and try again.

2. Tally.ERP 9 is running in educational mode. Use a valid license to complete this action.

3. A valid TSS is required to complete this action. Renew TSS and try again.