F5 iApp Exchange 2016 AD - Authentication Fail - UPN suffix mismatch

Hi Everybody

We are in the process of deploying Exchange 2016 / Outlook 2016 with F5 v11.6.0 (build 4.0.420) and APM. Our reference is the Exchange 2016 deployment guide (https://www.f5.com/pdf/deployment-guides/microsoft-exchange-2016-dg.pdf). We are using the latest iApp . Without APM it seems to be working fine, but as soon as we enable APM we are having athentication problems with Outlook Anywhere.

When we start Outlook 2016, it tries to authenticate using UPN firstname.lastname@company.com. The internal domain used however is company.local instead of company.com. So we are running into the problem described here (https://support.f5.com/csp/article/K12252), where UPN suffix does not equal domain suffix. I get the same error "... Please verify Active Directory and DNS configuration...." when doing a manual adauth test via CLI. We cannot seem to get the workaround descibed to work (replace APM AD Auth with LDAP).

Does anybody have a reference or can tell me if it is even possible to configure the APM (i.e. modify the iApp) to use LDAP instead of AD Auth with SSO in this scenario? Any advice would be greatly appreciated.

Thanks in advance.

Ingo