Important note about SSL VPN compatibility for 20.0 MR1 with EoL SFOS versions and UTM9 OS. Learn more in the release notes.
how do I remove a group member from the Sophos firewall authentication group?
I can add members to the group and view group members, but I unable to delete.
Hello Ishaq E
Unfortunately, there is no option to delete the Members of the Groups. However, if you would like to remove the member from the VPNUSERS group, you can assign a different group to that particular user.
For instance, in the below screenshot, you can see there is a user named "Tharun". 
To remove the user from this group, I assigned a different group for this user as seen below in the screenshot
Now the user is removed from the desired group as seen in the screenshot below.
Hope this helps. 
Ismail Jaweed Ahmed (Ismail)
Senior Professional Service Engineer
