Hello, What is the current network topology? If all the decos become red at the same time？ At that point, can you get internet from the modem directly? How often it drops internet and how do you sort...

Hello, what is the model number of your product? Is it Archer C7? What is the current problem? Please give us a detailed description. Thanks in advance. Good day.

Surely we will do. Thanks for your cooperation and support. Good day.

blade909 wrote thanks for your answer. its a pity cant recover original firmware for such a silly mistake. really the problem was caused by poor comunication between usb wifi adapter TL-WN823n V1...

Hello, the internal LTE antenna is welded into the PCB broad, while we do not suggest you to disassemble the product because of the warranty policy, we will not provide warranty service if the...

Hello, You can try to update the firmware as below: http://static.tp-link.com/MR6400_voip_beta_2016-09-06_15.01.35_1474602142560j.zip After that, please test whether the VPN works properly. Good day.