I'm having the exact same problem. I don't think it is network related (on my side), nothing has changed from when it was working ~5 hours ago.
It's working again now, I assume the answer was this: https://repl.it/bugs/p/repls-do-not-finish-loading.
If that is true and it's just downtime for upgrades on the Repl side, can you (Repl) change the messaging so we don't think it's an issue with the code/repl/connection? Site/server downtime is very understandable, it's only frustrating from the lack of clarity.
@smailliwretep The issue is that we can't really know with certainty what's causing the connection issue - it could be that our service is down, or it could be that a browser extension is interfering with it, or it could be that the network itself is blocking it (e.g. in a school or office), etc.