Exchange 2003 server (SBS) running normally without issue until today and suddenly everyone who tried to send an email got bounce with "550 5.7.1 Unable to relay".
Nothing in the system to my knowledge has changed.
Only thing I've been able to do meantime (which has worked) is to change the setting in Exchange System Manager : Default SMTP Virtual server >Properties > Access > Relay from 'Only the list below' to 'All except the list below' but I know this is NOT a recommended configuration!
(Box 'allow all computers which successfully authenticate to relay' remains ticked: did not change this).
With so many activities to perform, Exchange administrators are always busy in organizations. If everything, including Exchange Servers, Outlook clients, and Office 365 accounts work without any issues, they can sit and relax. But unfortunately, it…
In this video we show how to create an Accepted Domain in Exchange 2013. We show this process by using the Exchange Admin Center.
Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center.
Navigate to the Mail Flow >> Ac…
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online.
The email signature template has been downloaded from: