Hello @Tanvir124 ,

Welcome to our community.

What if you downgrade the firmware back to the previous version? For example, 

This sounds like an unstable WAN connection that may have been triggered by the firmware update. Here are some troubleshooting steps to help resolve this:

1. Verify cable connections:
Make sure the Ethernet cable between your modem and the router is connected properly. Try replacing it with a new cable (CAT5E or higher) to rule out cable issues.

2. Change DNS servers:
Log into the web management interface of your router at http://tplinkwifi.net, then go to Advanced > Network > Internet > Advanced Settings. Change the two DNS servers to 1.1.1.1 and 8.8.8.8.

3. Test direct connection:
Connect a PC directly to your modem to verify if your ISP Internet remains stable without the router in between. This helps confirm the issue is router-related.

4. Check router placement:
Make sure the router is properly placed in an open area instead of inside a cabinet or shelf to ensure proper ventilation and avoid overheating.

5. Disable certain features:
• Go to Advanced > NAT Forwarding > UPnP and disable UPnP
• Go to Advanced > Security and disable SIP ALG
These features may sometimes affect connection stability.