@Ranjithrao 

If you're experiencing unstable internet when your router is in Access Point (AP) mode, there are a few potential reasons and troubleshooting steps you can try:

1. Check the network configuration: Ensure that the router is properly configured in AP mode. You could refer to this FAQ: https://www.tp-link.com/support/faq/1384/.

2. Verify the connection between the router in AP mode and the main network: Ensure that the connection between your router in AP mode and the main network (e.g., modem or primary router) is stable. Make sure the Ethernet cable connecting the two devices is firmly plugged in and not damaged. Try using a different cable if possible.

3. Check the IP address conflict: Verify that there are no IP address conflicts between the router in AP mode and other devices on the network. Ensure that the router's IP address is within the same subnet as the main network and that it doesn't conflict with any other device's IP address.

4. Update firmware: Check if there are any firmware updates available for your router in AP mode.

5. Consider channel interference: If only Wi-Fi connection to the router in AP mode is unstable, there may be interference from neighboring networks operating on the same channel. Access the router's administration interface and try changing the wireless channel to a less congested one.