NTLM sophos xg (SFOS 18.5.1 MR-1-Build326)

What do you try to do? Because NTLM/Kerberos is a web based authentication, which uses SSO approach. Captive Portal is a Form based approach. 

in old version we can disable it from administration ->device access but now we can't.

i using ad sso but if fails ,captive portal didn't appear ,but show link with port 8091.

i face this issue after update sophos for the new version   

in old version we can disable it from administration ->device access but now we can't.

i using ad sso but if fails ,captive portal didn't appear ,but show link with port 8091.

i face this issue after update sophos for the new version   

Hello Mohamed,

Adding to what Luca mentioned, Try going to Configure >> Authentication >> Web Authentication.

Select Kerberos & NTLM 

Make sure that AD SSO is enabled in the Device Access as well. 

Regardss,