@Alan062 Thanks for your cooperation and reply. From the wired speed, the M4 should be working properly. I think it is more related to the wireless negotition speed obtained by wireless devices which...

@Unk What is the current network topology/diagram？ Do you use the Archer VR600 as 3/4G router mode with a 4G dongle? The VR600 supports Tether app in regular DSL modem router, but cannot use it to...

@Busta Thanks for your reply. Great to know that it works fine. You can enjoy the internet with our TP-Link router now. If need any further help, do not hesitate to contact us.

@leandersc What are the model numbers of the 2 routers? Are they both TL-WR841N? What is the current network topology/diagram? How do you connect them together? And what are their operation mode...

@Spentit Is it 5GHz-1 or 5GHz-2 cannot be connected due to the incorrect password ( even though it is correct)? If all the devices have the same issue--failed to connect to it? Have you tried to...

@Tale Not sure whether there is any special settings need to be done on the AirPort Extreme 5th gen cause the AirPort Express works fine. You can contact Apple tech support to get some help first. Or...