Microsoft office outlook cannot connect to onprem exchange server

1. Basic troubleshooting steps
Test the base connection:
cmd
ping exchange.yourdomain.com
Check the necessary ports:
cmd
telnet exchange.yourdomain.com 443
(If the Telnet client is not installed, you can test it via PowerShell: Test-NetConnection exchange.yourdomain.com -Port 443)
2. Client configuration repair
 Rebuild the Outlook configuration file:
Close Outlook.
Run:
cmd
outlook.exe /profiles newprofile /autodiscover
Certificate trust settings:
Access the Exchange OWA address (e.g. https://exchange.yourdomain.com/owa)
Export the certificate (.cer format) in your browser
Double-click on the certificate → Install to “Trusted Root Certificate Authority”
3. Server-side check
 Exchange service status:
powershell
# Check key services
Get-Service MSExchange* | Where Status -ne Running
# Verify MAPI over HTTP
Get-MapiVirtualDirectory | Select Server,InternalUrl,ExternalUrl
 Autodiscover test:
powershell
Test-OutlookConnectivity -RunFromClientAccessServer -ProbeIdentity OutlookMapiHttp.
4. Special handling of corporate environments
 Group policy tuning:
Ensure that the following policies are enabled:
Computer Configuration → Administrative Templates → Microsoft Outlook 2016 → Account Settings → Exchange
“Enable MAPI over HTTP”
“Use online mode”