Why can I only access ftp through vpn?

Question

VPN

Hello!
Actually, the essence of the question is in the title. At work is the Internet MGTS. On all computers except mine it works fine. On my own laptop, except for the inability to connect to FTP, the Internet drops every 3-5 minutes. When you turn on vpn, all problems disappear. All addresses are normal, not banned. The laptop works fine on other networks. Tell me what could be the problem

Answer 1

The green dot, for example, has similar problems. ssh , ftps break after a few minutes.
The problem is that the external ip is constantly changing.
Those. most likely the provider releases clients through several sock servers and changes them too often