Issues connecting to server manager from several browsers

NethServer Version: 7.7.1908
Module: TLS Policy
Using Firefox Beta 73 i receive SEC_ERROR_BAD_SIGNATURE message when I try to access to NethGUI and cockpit.

More details about the setup:

  • No public hostname, no public signed certificate
  • TLS Policy 20181001 (latest available)
  • Installation started from 7.6 upgraded time to time, now fully updated.

With Chrome 79.0.3945.117 i can see the login page, i can input data for login but i do not connect to Cockpit (page is not loaded); NethGUI works fine.
With Waterfox 2019.12 which is firefox 68 based, no issue at all on NethGUI or Cockpit (minor errors into upper right side of the screen for cockpit, not a thrill).
Computer that i am using has antivirus which checks and filters HTTP and HTTPS, but i have similar issue into another compuer with a different antivirus.