Windows 8/8.1/10 Unable to connect to the game server.

I am having this error all the time.
I already tested Windows 10 and 7.
I've used FlushDNS in CMD I've used this command:
netsh int tcp set global ecncapability=disable
I've tested it on different computers and I still have the same error. (Computers at my residence.)
I already used DNS 1.1.1.1 - 1.0.0.1 - 8.8.8.8 - 8.8.4.4
Sometimes I turn off the computer and the internet, so it works, but after a while, if I change channels or enter the Cash Shop, I disconnect, and I have this problem again.
I already put the game as an exception, I turned off the firewall but nothing worked.
I don't know why it sometimes works without doing anything.

My Computer:
Processor:i3 4160
GPU: RX 580
RAM: 8GB
Internet: Fiber 60MB