The sync fails with an error: Failed to authenticate vault. Cause: Vault API call failed. Vault transaction id: http-VLT-US-EAST-1-PRODUCTION-8-8741631-31 response status: FAILURE error type: USER_LOCKED_OUT cause: The user is locked out. in CRM Approved Email Admin tab.
The Vault integration user is locked in Vault.
Refer to the following articles to reset the password and unlock the Vault integration user.
Vault Help Documentation: N/A