Suddenly Outgoing mails stopped. with below error
Error : Exchange Toolbox – queue Viewer
4.4.0 Primary Target IP Address Responded with: “535 Authentication Credentials invalid.” Attempted to failover to alternate host, but that did not succeed. Either There are no Alternate hosts, or delivery failed to all alternative hosts.
Solution – Smart Host Authentication – Credentials were invalid
In Send Connector Properties . Smart host authentication password was changed. Had to Update the new password.
Without any service restart mail flow started flowing.
Optional – Restart Transport service to refresh.