When I try to send data an error message saying Cannot connect to server

Question:

The Web browser and Materials Box both display correctly, but when I try to send Notes etc. between students and teachers an error message saying "Cannot connect to server" is displayed at the bottom right-hand corner of the screen and I cannot send the data.

Answer:

It is possible that there is a problem with the settings of the server used for the external connection.
Sometimes the error message HRESULT"0X80072EE4" is also displayed.

Try the following two tests. If you get an OK then there is no problem with the filter.
https://n.loilo.tv/file_access_check
https://n.loilo.tv/health_check

If you do not get an OK for one of the above tests, try allowing access to all the sub-domains with .loilo.tv or try excluding it from the contents filter.