VPN Access to multiple windows domains

Hi, I am having a VPN issue that i cant seem to figure out. I have 2 separate domains on the LAN.

If User-A who is registered on domain-A remotely connects to the VPN it authenticates and connects without any issues.
If User-B who is a member of domain-B tries to connect to the VPN it fails. If I take User-B Laptop and make it a member of Domain-A on the LAN and then attempt to connect remotely it authenticates and connects without any issues.

I am using L2TP, with individual secrets.
I tried mschap2 disabled as well as mschap1 and mschap2 disabled.
I tried different DNS server ip addresses on each user secret (DNS of the respective domain server)
Mikrotik RouterOS 6.42.12
RouterBOARD 931-2nD r2


Please assist.