There are tips in this and other CNET forums about WiFi. Links will follow.
I'm encountering folk that demand the internet and all site always work well. Sadly that was never what the internet was going to deliver and how to hold that discussion can be unacceptable to some. If trying again works, it could be some monetary congestion at that site.
1. Use Google's DNS (plenty of web pages on that!)
2. Improve your WiFi. Read
We are having internet connectivity problems. Some sites load normal while at the same time other sites will load slowly if at all. I have run a speed test while a site is trying to load and the speed is normal. This problem is usually in the mornings but not always. Does not seem to be any reason for connectivity. I have contacted our provider and all seems OK. We have the problem with explorer, firefox and chrome so it is not a browser issue. It will clear up unexpectedly.