How to prevent internet disconnection issue during Online exam?

I have a web application developed in Asp.Net Core MVC with the SQL server. This is an LMS solution already live in some schools. The exam module is very mature but the problem I am facing is the internet connection. The connection between some schools is not stable. The student gets disconnected during the exam and a lot of time wasted when the internet disconnected.

How to prevent this?

Is there any solution to the above-given problem?

Should I use the offline exam module?

Or any other solution?