ADFS : Non domain-joined proxy

All our proxies are domain-joined albeit in a different zone.

Recently, I was involved with a client whose proxy was non-domain joined i.e. a workgroup.

When installing the proxy, you need to enter the credentials of the ADFS service account.

Battled to get this to work and then I remembered that this was not domain-joined and consequently, you needed to enter the sAMAccountName in the form:

domain\user

where the domain is the one that ADFS is installed in.

That did the trick.

Enjoy!