In most cases, rebooting your VBox will address the problem.
If you are able to check your connection speed, make sure you have sufficient bandwidth. The minimum recommended bandwidth is 5 Mbps per VBox. Please note that speed to the VBox can be impaired by the quality of your router or your modem, or if unrestricted file sharing and remote backup software is running as these consume all available bandwidth.
If after rebooting your VBox, you are still having some problems, please contact us and we will help you resolve the issue. We are available everyday 10:00 am - 9 pm EST by phone, chat or email.