If you are having trouble viewing a some students submission it may be a firewall issue. To verify whether or not this is a networking issue, try to see if a different internet connection outside your current network shows the file correctly. This likely indicates there is an issue reaching Peergrade's files due to the network's configuration.
You may be getting error such as this one:
Chrome 70.0 (November 2018) will show an error like:This site can't be reached
peergrade.s3.eu-west-1.amazonaws.com unexpectedly closed the connection.
The error may be slightly different depending on the browser and the current version.
How to fix it
Check with your IT department that our file URL isn't blocked on your school firewall. If your school is blocking our URL's you can ask your IT department to whitelist our URLs so that you have access.
URL's to whitelist
November 2018 URL Change
Around the time of November 2018, Peergrade changed it's AWS url:
New URL: peergrade.s3.eu-west-1.amazonaws.com
Old URL: peergrade.s3-eu-west-1.amazonaws.com