This issue could be occurring due to the outdated driver in your Dell Laptop. To fix this just follow the steps.
Uninstall the current Drivers and Reinstall the Updated one.
1. Open Device Manager and Find the network drivers
2. Uninstall the driver by double tap on it.
3. You will get a pop up to uninstall it, just put the check mark next to “delete this driver” option.
4. Now, Restart your computer to complete the uninstallation.
5. After restarting your computer visit this link to download the latest drivers. support.dell.com
6. Type in Service TAG number and choose your operating system.
7. Now download the network drivers or WIFI driver and install them.
This should resolve your problem. If your problem still persists you can contact Dell customer care to get the help you need.