After updating SSL certificates on Exchange Server 2013/2016 and rebooting, you may encounter HTTP error 503. In Event Viewer you might see “An error occurred while using SSL configuration for endpoint 0.0.0.0:444”. This typically appears when logging into ECP or OWA and is caused by incorrect SSL bindings in IIS.
Steps to resolve the issue:
Check IIS Bindings and reassign the certificate on port 444
Command-Line Fix (if needed):
netsh http show sslcert
netsh http delete sslcert ipport=0.0.0.0:444
netsh http add sslcert ipport=0.0.0.0:444 certhash= appid={4dc3e181-e14b-4a21-b022-59fc669b0914}
(Replace with the actual certificate thumbprint.)
References: