@Admin user login failed while login to web GUI

Hi DevK,

Thank you for reaching out to Sophos Community.

Kindly check the logs( access_server.logs), to give us further insights

• Log file details

Or

Kindly try to disable the appliance access by doing the following in Advance shell and then kindly try to change it via GUI.

• system appliance_access enable ( be advised that traffic will be disabled,schedule this activity)
• system appliance_access disable (once done)

For reference

•  Sophos Firewall: What to do when the Web Admin is not accessible