v18 to v19 upgrade issue

Hello Madni Malik,

Thank you for reaching out to the community, if you wish to continue only with the STAS authentication then please disable the following options under the administration > device access: 

STAS only uses client authentication, so keep that option enabled !! 

And please follow the best practice of configuring STAS: https://community.sophos.com/sophos-xg-firewall/f/recommended-reads/125318/sophos-firewall-best-practice-for-stas

you mean to say that i have to disable check box under captive portal??? please confirm??? i also disabled it.

my reqruirement is that 1str of all STAS authentication will occur, if STAS authentication does not happen then it willl go for NTLM . please advise. 

Yes, if you want to use STAS as the auth method then captive portal, AD SSO and Radius SSO is not required !!

if AD SSO is checked then will it make some disturbance??? 
my reqruirement is that 1str of all STAS authentication will occur, if STAS authentication does not happen then it willl go for NTLM . please advise. 

if AD SSO is checked then will it make some disturbance??? 
my reqruirement is that 1str of all STAS authentication will occur, if STAS authentication does not happen then it willl go for NTLM . please advise. 

AD SSO is not related to STAS authentication, so no it will not disturb your settings. STAS uses "Client authentication" and that should be enabled !!
If you want NTLM as a backup authentication then, leave it be, if not then untick the option !!