Can't connect to a single specific Minecraft server, yet it works fine on other computers

Whenever I try to connect to a specific SMP server, it is sometimes extremely laggy (5-second delay) and sometimes it works great. I’ve been having this problem for only a couple of days. It’s pretty random as to which I will log into and the lag can last for hours on end.

This server is hosted in New Jersey, yet I can connect to servers hosted in the UK no problem. It seems to be only this server that I have trouble connecting to, and what is weirder is that I can get on using my brother’s laptop (which is arguably worse) and it will run flawlessly no matter what!

Does anyone have a clue why I’m only having this issue with a single server only on my computer? I use Minecraft Java Edition 1.16.2 on a Windows 7 computer.