I've seen this specifically on the IndexNow service, but I monitoring in place to monitor IndexNow and in those cases, it was not my server, but the route in between my server and IndexNow.
So this is most likely not a problem on your server itself, but somewhere on the internet in between you and the destination server. The internet is like the roads/highway system.
You leave your house and mid-way through your trip, it's possible you run into traffic. It's not a problem on your source or destination side that made you late, but instead something along the way. This is saying there was no response within 10 seconds of the request so it gave up waiting. It does not mean your server was blocking it, but that there was a temporary issue that typically goes away within a few minutes.