Business Central - Azure SSO Redirect Loop

 

Azure SSO Redirect Loop

I noticed an odd issue when both Business Central application servers were running at the same time, in which the Azure Single Sign-on page would constantly loop round and round after entering your credentials. If I disabled IIS and stopped the Business Central Service Instance on one of the servers, the issue went away.

In Azure, I noticed that the following setting was enabled on the Production Application Gateway, but was disabled on Test. Under Settings > Backend Settings > navServiceTierBackendHttpSettings > Cookie-based affinity.

The application gateway can use cookies to keep a user session on the same server. You can enable this feature if the client supports the use of cookies.

I enabled Cookie Based affinity for the navServiceTierBackendHttpSettings port 443 and this resolved the issue.