Your e-Mandate registration fails when the authentication using net banking or your debit card is unsuccessful. This happens if you close the authentication window before entering your credentials or if you enter incorrect credentials. Zerodha cannot determine the specific reason for the failure; only your bank has this information. If your mandate creation fails, you can recreate it from Console.
Banks do not support e-Mandates for customers using current, joint, and NRE-PIS bank accounts. If you cannot set up your e-Mandate successfully on Console, you can place standing instructions to automatically transfer money through your bank's net banking portal by adding Zerodha's account as a beneficiary.