If you experience that Trelson complains about network errors even though you have verified that the internet is available, you can check if your firewall is blocking the following domains:
https://accounts.google.com/*
Needed to be able to log in to their Google account.
Needed to be able to log in to their Google account.
https://*.googleapis.com/*
https://apis.google.com
https://ssl.gstatic.com
To send API requests to Google services.
https://assessment.trelson.com
Internal services for Trelson.
https://www.wiris.net
https://data.wiris.cloud/
Support for mathematical equations (equation editor).