Hi David, if it works inconsistently, that is hard to diagnose. Firefox uses a web content cache to speed up rendering of previously visited sites. However, it sometimes will "race" the cache against your network connection making it unpredictable whether you will get a freshly retrieved file or one from the cache. You might want to flush out the cache in case it is randomly introducing obsolete files into the mix. The following article has the steps: [[How to clear the Firefox cache]]. Assuming you do not want to sign in to all your open sites again, please select only the web content cache and don't clear the cookies and site storage. Any difference?