This keeps on happening can you help me:
Edit: On the next day, I tried on another wi-fi network and it was fixed. I don't know if it was because of that wi-fi network or because yesterday the Showdown server was down.
The reason you keep getting that message is because of Showdown's provider end.
Pokemon Showdown is currently down due to a technical issue on our provider's end. This means we can't do anything about it but wait for them to fix it. There is no ETA on when it will be fixed
Source
Since they don't know how long it will take to fix the issue, if you want to play Showdown still, you'll have to try another Showdown Server. Some people are using a Chinese Showdown server, and a Staraptor Showdown server for lower tiers, just for a couple of examples.