The problem#
A website that I had been using every day suddenly stopped loading. Connecting to it just timed out, like the server was completely down. I figured it was a temporary interuption in service, but several hours later, it was still not working and there was no status message on the organization's main site about an outage. So I was suspicious the problem was somehow on my side.
The solution#
There's a lot of different reasons for the same behavior, so I can't offer one solution. But in this case, I reset my internet connection by clicking the "reconnect" button in my router's WAN settings. With my ISP setup, that grants a new IP address, which somehow fixed the issue.