Download failed (Return: -, SockError: the network subsystem can not be used)

Apologies I have searched the FAQ and I can not find an answer.

I changed VPS, I migrated my projects and started them. I am running public proxies through GSA SER and executing them on a well specified machine. When I started the projects, I still get the same error message when trying to create links. The error message is:

Download failed (Return: -, SockError: the network subsystem can not be used)

When reading other frequently asked questions, the answer is proxies (there are many SOCK proxies that are used in publicly discarded proxies) or a Firewall problem. Has anyone else found this problem and what did you do to fix it?