I tried running
Test-OutlookConnectivity -GetDefaultsFromAutoDiscover:$true
but it says it doesn't recognize the parameter -GetDefaultsFromAutoDiscover:$true
Here's the values for Get-OutlookAnywhere:
ExternalHostname : legacy.domain.com
InternalHostname :
ExternalClientAuthenticationMethod : Ntlm
InternalClientAuthenticationMethod : Ntlm
IISAuthenticationMethods : {Ntlm}
ExternalHostname : mail.domain.com
InternalHostname : clippers.domain.local
ExternalClientAuthenticationMethod : Negotiate
InternalClientAuthenticationMethod : Negotiate
IISAuthenticationMethods : {Negotiate}