After yet another downtime (the third within a short time) we figured out that the problem seems to be related to the GOF domain name "thegangoffive.net.We don't know the exact nature of the problem, but the problem does not exist anymore when rather than using the the domain name we change the setting to the default of http://z7.invisionfree.com/thegangoffive/index.php?. So for the time being we should use that url rather than the original domain name. We are going to continue seeing if we can get the domain name back to work properly.