You may have a firewall blocking the SoftChalk Cloud website. We suggest that you contact your technical network people to have the following web addresses added to the allowed sites in your school firewall/network filter:
For Cloud connectivity, the following domains will need to accessible for both OUTGOING and INCOMING traffic:
http://softchalk-cloud-files.s3.amazonaws.com
...
All of these connections are over TCP.
For more details on SoftChalk Cloud, please see the FAQ:
How do I get started with SoftChalk Cloud?, the SoftChalk Cloud Guide and the SoftChalk Cloud website.