Could you please try temporarily:
- Disabling your firewall (note that this may be a software firewall on your computer or a setting on your network router)
- Disabling any antivirus or parental control software
If the issue continues then please get in touch, considering the following questions.
- Is this issue only happening for 1 student on their home computer?
- Is this error occurring every time?
- If you are on wi-fi, do you have a strong internet connection?
- Are you able to try connecting on another network, a mobile phone hospot can be a good test.