One of our business computers always fails to enter to another networked computer

Hello people, sorry if the title is a bit uninformative , English is not my first language.

So we have a problem with one of our computers here at the buisiness , we are all networked through the same router , and my computer even uses WIFI because it's too far away to connect through a cable.

My computer and another employee computer is connected to the main engineer's computer.

We do that just by typing \desktop-xxxxxx\ on "run" and it lets us connect to his shared hard drive.

Problem is , the other engineer's computer is always failing to connect at the start of a new day , I don't know why

We tried disabling firewalls, renewing IP's , refreshing the network , disabling antiviruses , nothing works.

He always gets this error: https://imgur.com/a/Qa68C3C

My computer never have these problems, and his computer can connect to all of the computers so nothing is blocked.

I was out of ideas so I hope you guys could help me.