To resolve the issue where your TL-WA850RE shows "no internet connection," follow these steps:

1. Check the Internet Source:

   Ensure your main router or modem is connected to the internet. If the main router has no internet, the TL-WA850RE won't work either.

2. Reboot the Extender and Router:

   Power off both the TL-WA850RE extender and your router. Wait for 30 seconds and then power them back on. This can often fix connectivity issues.

3. Verify Signal Strength:

   Check the placement of your TL-WA850RE. It should be in a location where it can receive a strong signal from the router. A weak signal can lead to intermittent internet issues.

4. Reconfigure the Extender:

   If you recently moved or reset the device, reconfigure the extender using the TP-Link Tether app or web interface. Follow the setup steps to ensure the extender is properly connected to the router.

5. Update Firmware:

   Ensure the firmware of the TL-WA850RE is up-to-date. Visit the TP-Link website, search for your model, and download the latest firmware. Install it to ensure your device is running efficiently.

6. Check IP and DNS Settings:

   Sometimes, incorrect IP or DNS settings can cause no internet issues. Make sure your device is set to receive IP and DNS settings automatically from the main router.

7. Factory Reset:

   If all else fails, perform a factory reset. Hold the reset button for about 10 seconds, then reconfigure the device from scratch.

If the problem persists, contact TP-Link support for further assistance.