NDRs that contain error code 5.0.0, 5.7.1, or 5.7.3

Are you getting an error sending email through Exchange? Possible causes of NDRs that contain error code 5.0.0, 5.7.1, or 5.7.3 Error code 5.0.0 or 5.7.1 may occur if the following condition is true: Your Exchange computer is listed as a messaging server that sends unsolicited commercial e-mail. Error code 5.7.1 may occur if one [...]