I cannot connect WPMUDEV, I receive the following error:
And the hosting company replied:
Or web hosting does allow fsocketopen and CURL but it does not allow the connections to call back on itself. Maybe something has changed on the plugin if it has worked on your previous installations? It's worth checking if the plugin does a call back onto it self and for that you will need to contact the plugin authors. If it does then I'm afraid the plugin cannot be used with our hosting.