Ongoing Connection Issue in bf4 Client Closed Down Connection Port 3659 UDP

I am writing to express my deep frustration regarding a persistent issue I have been facing while playing Battlefield 4. I constantly receive the following error message during gameplay:

Game disconnected: Client closed down connection. Check your network connection and make sure that port 3659 [UDP] is open.

This issue occurs frequently, ruining the multiplayer experience entirely. Despite my extensive efforts to resolve it, the problem still persists without any improvement.

Here are the steps I have already taken in an attempt to fix this issue

Port Forwarding:
I have manually forwarded port 3659 UDP on my router. I ensured it was correctly configured and applied the settings after each change.

Firewall Configuration:
I added the required port and Battlefield 4 as an exception to my firewall rules.
I even went as far as disabling the firewall entirely for testing purposes, but the error still appeared.

Router Tools:
I used third party tools designed to check and open ports, confirming that port 3659 is accessible yet the issue continued.

Network Changes:
I updated my Ethernet drivers, switched cables, reset my modem/router multiple times, and even changed DNS settings.

System Adjustments:
I tried running the game with administrator privileges, cleared origin cache files, and reinstalled the game several times still no success.

Despite doing everything humanly possible, the error continues to haunt my gameplay, disconnecting me almost every time I try to play. It’s incredibly discouraging, and I feel completely helpless.

I would greatly appreciate any concrete solution or technical advice that might finally fix this problem. I’ve been a loyal Battlefield player for years, and this issue is making it nearly impossible to enjoy the game I love.

Please help me resolve this once and for all.