Exchange 550 5.7.1 RESOLVER.RST.AuthRequired; authentication required

exchange-server-2010

If you are trying to send email from your web server to a distribution group email and it isn’t going through, and the Exchange log shows the following error “550 5.7.1 RESOLVER.RST.AuthRequired; authentication required” then follow the steps below to fix it.

550-exchange-error

Exchange 550 Error

Step 1

Click on the the Distribution Group name that you are having trouble with via the Exchange Management Console and go to properties.


Step 2

Click on the “Mail Flow Settings” Tab.

Step 3

Click the “Message Delivery Restrictions” item.

Step 4

Click the “Properties…” button.

Step 5

Uncheck the “Require that all senders are authenticated” item.

Step 6

Click “OK” button.

Step 7

Click “OK” button again.

require-senders-authenticated

Now try sending again, watch your logs in Exchange via the Toolbox Message tracking tool and hopefully you will now have success and no error.


  • Mohannad Khaled Maglad

    dear , can i get solution with out uncheck box for authentication ,