TLS error Nextcloud sync client Windows 2016 server

This error only appears on the W2016 server.

On Windows 7/8/2008server/10, Linux Fedora\Ubuntu synchronization client connects normally to this server.
Let’s Encrypt or self signed certificate, does not matter, i get the same connection error
How to Fix IT?

The client connected using a proxy.
After installing the connection without using a proxy server, this certificate error has disappeared.