Wrong username / password when connecting via network to a PC, what is the reason?

Question

WiFi

A simple local network is organized via Lan and WIFI using a router. Network discovery is enabled on all PCs. The working group is the same for everyone. The laptop is connected to the network via WIFI, in the "Network" section it sees all computers. Connects to all but one PC-1 (windows 10, LAN). It requires a username and password, I enter it - it writes the wrong username / password. There is one main microsoft account installed on this PC-1, not a local one.
Tried to take the username from "Local Users and Groups" - still wrong login/password. On other computers, the situation with PC-1 is the same.
What is the reason and how to fix it?

Answer 1

As mentioned above - point 3.
Disable permanently the MS account and not use it in principle, it is useless. After that everything will work.

Answer 2

How to overcome this problem