Database Mirroring login attempt by user ' ' failed with error: 'Connection handshake failed. The login ' ' does not have CONNECT permission on the endpoint. State 84.'. [CLIENT: ]

You may receive an error similar to below message in server’s log which stops database mirroring:

Database Mirroring login attempt by user ' ' failed with error: 'Connection handshake failed. The login ' ' does not have CONNECT permission on the endpoint. State 84.'.  [CLIENT: ]

This message actually informs that your security configuration for the mirroring protocol is broken. Hence you can easily rectify this error by fixing the permission on endpoint using below syntax:

grant connect on endpoint::[endpoint name] to [account]

Example:

Below command will fix this issue assuming end point name is “mirroring” and account name used is “cdba\test”

grant connect on endpoint::mirroring to [cdba\test]

Note: If your mirroring is suspended then you have to resume mirrirong after this command.