Those page load issues are internal server errors (error code 500, which isn't exactly helpful). I get them often, including when running Pywikibot so it's safe to say the problem is universal. I would expect that somewhere in the logs something is throwing out errors when this happens, but since code 500 is so general, there's nothing we can do to be more specific. Someone may need to sit there, reloading pages, and watching the server logs live.