Failed to verify server information

I have install Seafile server in Windows Server 2016. All works fine, but when I tried to connect with the server, using Seafile Client, this error appears: Failed to verify server information.

What can I do to resolve?

Thanks.

A little more info on your server (and possibly client) would be helpful. Such as: Do you use a self-signed SSL cert on the server? What kind of personal firewall/AV-programm do you use?

I have just install the operating system, Windows Server 2016 Standard. There is no AV or SSL. Only install Seafile server and change the ports, 8000 and 8082 (new ports 330 and 331), I open it in the router and I can view the server via browser. With windows client, I can see the folders, but when I tried to sincronice the folders, the error appears…

Windows installs are obosolte and not maintained. Consinder switching to Linux or use Docker.

Yes, I know but I have 4 server like this working. The same type installation and it work fine. But I don’t know what happens in this installation.