NTLM specified. Downgraded to Basic Auth (and/or SSL) but downgrade not supported

Question

Hoping you can provide some assistance regarding an ongoing issue we having accessing an internally hosted application via Citrix VPN on Windows 10 machines.

This issue appears to be mainly linked to the new Windows 10 laptops connecting via an updated Citrix client. The error users are getting when trying to access the application over VPN as below:

java.lang.UnsupportedOperationException: NTLM specified. Downgraded to Basic Auth (and/or SSL) but downgrade not supported.

the application works fine for users connected over the LAN, once they disconnect from LAN, and access over VPN, this issue occurs, Any help and guidance as to what the issue could be would be appreciated

Regards, Craig