When you change AutoDiscover settings for users, it can take up to 2 hours until the cached data on each Exchange Server is invalidated and the new AutoDiscover configuration is sent as a response to new AutoDiscover request.
You have to force a service and a application pool restart to activate your configuration changes immediately:
- Service: MSExchangeServiceHost
- Application Pool: MSExchangeAutodiscoverAppPool
These restarts need to be performed on each Exchange 2013/2016 server in your infrastructure serving AutoDiscover requests.
Use the following two PowerShell cmdlets to simplify this task:
Get-ExchangeServer | ? { $_.AdminDisplayVersion -like '*15.*'} | % { Invoke-Command -ComputerName $_.Name -ScriptBlock {Restart-WebAppPool MSExchangeAutodiscoverAppPool } }
Get-ExchangeServer | ? { $_.AdminDisplayVersion -like '*15.*'} | % { Invoke-Command -ComputerName $_.Name -ScriptBlock {Restart-Service MSExchangeServiceHost } }