Cant pass trough loggin screen in Macos

Hello !
I have some problems when trying to connect with Macmini when the computer is on the loggin  screen.

Communication is established, but after I try to connect, the teamviewer hangs for a while and then disconnects.
If I try to connect again after, I go back to the loggin screen and everything repeats itself.
If I try to connect to a Mac already logged in , or log on directly in Mac keyboard instead of by the teamviewer the connection normally occurs.

This occurs when I try to log into a Mac outside my network (internet), when I try on a Mac inside my internal network, it works normally.

I have tested and verified the passwords, I have already done the tests on more than one computer, in more than one place and in some diferents Macs, and the result is repeated.

If you know anything that might help, thank