Microsoft Exchange migration shows the error "Could not establish trust relationship..." when Test button is clicked


Whe configuring a migration strategy from a Microsoft Exchange server, the Test button gives an error message which includes "Could not establish trust relationship for the SSL/TLS secure channel". This happens even if the option to allow self-signed certificate is enabled.


Although the option to allow self-signed certificate is enabled, the migration utility will still validate the certificate, so errors in the self-signed certificate (apart from the expected untrusted roots) will still produce an error. You may need to bypass this and try to use any certificate. To do this, the following registry key needs to be added:

[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Mail Enable\Mail Enable\Migration\ExchangeWS]
"Bypass Certificate Validation"=dword:00000001

You will need to add the Migration and ExchangeWS keys into the registry as they don't exist by default. After adding this DWORD value, then the certificate will be accepted.


Class:TRB: Troubleshooting (Configuration or Environment)
Revised:Monday, May 25, 2020