Some add-on is causing my internet to go down

This is a really weird problem but my Kodi standalone system on Linux results every evening around 7pm my internet going down.
If it is connected then the internet connection drops and if I disconnect it its back.
After 2-3 hours it fixes but its highly irritating and I’ve already beat the ISP and the router company over it but have just identified this as the issue.
It must be some add-on causing it as its at a specific time that it happens.
If some has had same problems can they help identify which add-on is causing it or what the problem solving can be?