We suspect this might be caused by your school or district's firewall blocking our framework for Real Time or Live Real Time messaging. Please add *.ably.io, and *.ably-realtime.com to your safe/allowed domain list. Whoever is in charge of your school or district's IT department can adjust the firewall or SSL settings to accommodate this Real Time feature.
It is also possible that it may be related to a cache issue in the browser you're using. We recommend clearing your browser cache to see if this will resolve the issue on your device.