The error only pops up for one server, I've tried reinstalling Minecraft and changing the version, but I don't know what to do.
First, next time please include more information about your question, such as the server you are trying to join, or general PC specs - OS etc, or if your game is modded.
To troubleshoot the problem, temporarily disable the firewall. Control Panel > System and Security > Windows Firewall (or just type in “Firewall” in the Start Menu search box)
Then, on the left disable the firewall "Turn windows defender firewall on or off" - Try to join the server with this off.
IMPORTANT: Turn firewall back on after testing - Leaving off can allow malicious programs to gain access to your computer.
If this solved your problem, you can whitelist (allow) minecraft to bypass the firewall - "Allow and app or feature through Windows Defender Firewall"
You will need to allow Java(TM) Platform SE Binary
If that doesn't work, also try and whitelist the minecraft jar that you play on.
Do this by finding "Allow another app..." then navigating to your minecraft folder. (Browse > Windows Drive > Users > Your user > Appdata > Roaming > .minecraft > versions, then click into the folder of the version you play, and whitelist 1.XX.X.jar (eg: 1.13.2.jar)
If this doesn't work, there are many other reasons that can cause this. It could be server-side - You should contact server administrators, or your ISP could be blocking your traffic.
Feel free to reply/edit