Unable to add machine to AMS

I have found this error message multiple times on the forum and either no solution posted or the solution didn't work for me.

When trying to add a machine in a different subnet to AMS, using remote console or AMS I get the following error messages:

Code: 20,250,646(0x01350016)
LineInfo: 0x8D165E86FB8195FF;
Module: remote_install_command_addon_vs_39029
Message: Failed to add machine '10.0.5.250' to the management server.
Code: 24,641,537(0x01780001)
LineInfo: 0x3EAC2BD32D84C047;
Module: remote_install_command_addon_vs_39029
Message: Failed to add machine '10.0.5.250' to the management server.
Code: 21,430,291(0x01470013)
LineInfo: 0xA76A04993E79384C;
Module: mms_vs_39029
Message: Authentication has failed.
Code: 21,430,290(0x01470012)
LineInfo: 0xA76A04993E79385E;
Module: mms_vs_39029
Message: Failed to migrate data to the license server.
Code: 13,238,285(0x00CA000D)
LineInfo: 0xEC81F6265C05818A;
Module: mms_vs_39029
Message: Failed to establish connection. Check the specified machine address.

I can install the components remotely, I can connect to the console, AMS shows the server registered in licenses section, I have followed the steps in https://kb.acronis.com/content/46942 but have not contacted support directly yet.

The machine was connected to an old install of AMS on another server fine but won't connect to the new one.

Any help appreciated.