No idea as well. Hope you can get a solution soon. Any update, share here

The two antennas of the MR6400 are working collaboratively. If you want to change the channel, you must change both of them, otherwise it can't make the signal better.

what's the current firmware version and hardware version of your MR6400? Did you check tp-link website for the new firmware?

Hi MilanFan, you can upgrade the firmware first. Contact tp-link support it this can't solve the issue. Perhaps they meet this same issue before.

Here is an troubleshooting instruction for port forwarding, you can have a look: http://www.tp-link.it/faq-785.html Make sure the camera can be accessed internally via its IP plus port number first....

Hope it can work.Any update, can you share here ?