OPC Interface Hostname error and Buffer Off

Hi! Im trying to set up an OPC DA interface and I have some issues with the hostname. The PIServer/collective name is a something like AX-SERV, the SDK Member is similar to AX-SERV-01 and the host domain path is similar AX-SERV-01.OPCPLC (not using the real server names), thing is that everytime I try to set up the interface and select the host domain name for the API Hostname section (which is available in the dropdown list)I get an error indicating that the hostname is incorrect. Also the buffer status at the bottom changes to Off with an enable button. If I click on the Enable button it takes me to the buffer server configuration but although I go through the process and it says connection successful, when I return to the interface screen, the Buffer still says Off, and I keep getting the incorrect server error.

 

It is only working if the SDK Member and the API Hostname are the same.

 

Any Ideas on whats happening and why I cannot use the pathname in the hostname section?