Here are some steps to diagnose why your internet connection is dropping:

1. Check your modem settings: Check that your modem is configured with the correct settings for your Internet Service Provider (ISP).
2. Update device drivers: Make sure that your device drivers are update and compatible with the latest version of your operating system.
3. Change your firewall settings: Make sure that the firewall settings on your device are not overly restrictive.
4. Check router configurations: Make sure that the router configurations are compatible with the router type, traffic type, and number of users.
5. Reset the router: Reset the router and try to connect again. This will help identify if the problem is with the router.
6. Check the network bandwidth: Make sure that the network and the bandwidth are sufficient for the number of users and type of traffic.