This can happen when its failed to connect to the server or its been removed, so what happens is you get an fail to connect.
Also it can happen if you server has blocked content to, as for log file that's if you want to send an error report you can set this up in setting.
The only way round us to just use another link, make a note of the ones that don't, as some add-ons allow you to pick the links you want.
I think in Phoenix if you press menu and in the sub menu press add-on setting, you go to the right you can select the links you want by highlighting them or un-highlighting them.
Hope this helps