Cannot add accounts on domain joined client PC

In emClient V9 and also in Beta V 10.0.1495 I cannot add accounts when the client computer is member of an Windows AD domain and the mailbox is hosted by an Exchange Server not member of the clients domain.
Automatic setup and manual setup does the same thing: It uses the Windows account credentials to log on on the Exchange Server instead the credentials provided by me.
I can see the wrong username in the Eventlog on the Exchange server.

The only way to get the accounts added and connected so far is:

  • Start Windows 10 Sandbox
  • Install emClient
  • Export account settings to XML (include password)
  • Import the XML on emClient on domain joined PC
  • Exit (and discard) Windows sandbox

This is not really usable for the average user, I think.

In an old post I read the same problem for connecting to O365 with domain joined PC - there was said, it’s fixed in V9:

Is this a still open issue?