Unable to view OAB and OOF via Outlook Anywhere published through TMG/ISA

This post is about a problem where Outlook was working fine through TMG publishing rule, however when TMG Admin tried to access OAB and OOF through Outlook he got an error. To bypass Outlook he tried to access https://mail.contoso.com/ews/exchange.asmx and got 403. The 403 was coming from Exchange vdir /EWS/, here an example of the…