AD authentication failing after update 12000

Same issue as reported by other user:
https://pitstop.manageengine.com/portal/en/community/topic/failed-udate-to-12-0-1200

After latest upgrade to patch build ManageEngine_ServiceDesk_Plus_12_0_0_SP-0_1_0 AD authentication is failing for all users including Technicians.

Only local authentication with old admin account is possible but visual home.screen missing all personalization, AD authentication not working.

Unfortunately the administrator account is not a “technician” anymore, substituted by one of our 5 technicians. Then, we are unable to enter in the admin mode to check if some additional settings is necessary.