@MarianoC 

Hi MarianoC, can you please confirm how does the Archer C7 crash when you connect the Samsung A50 or A51 to the 5G network? Are all the LEDs on the C7 flashing off then on for minutes? How will it recover then?

What is the current 5G wireless settings on the C7, you may try to change the wireless channel, channel width, change security to WPA2-PSK, AES, then reboot it manually to confirm.

@Kevin_Z Sometimes it reboots, sometimes continue working, but everyone connected to 5ghz network get's no internet. For this to happen the A50 or A51 needs to start getting traffic, like watching a video on youtube. If they just gets connected and do nothing, everything works. I tried changing the channel, width, security and nothing changed, it behaves the same. No entries about any problem in the router log. If the A50s connect to 2.4 there is no problems. Anything else I can change?

Thanks,

Mariano.

@MarianoC 

Try to reset the C7 to factory defaults, leave the A50 and A51 disconnect from the 5G network, then monitor the stability. If this always works fine, ensure there is no special settings on the C7 for the devices, try to connect the A50 or A51 to the 5G network, monitor again how long you will have a stable connection.

BTW, have you enabled the private address on the A50 and A51? Check it as below:

Go to Settings app -> Network and Internet -> Wi-Fi ->Connect to router’s Wi-Fi -> Tap the gear icon next to the current Wi-Fi connection -> Advanced -> Privacy -> "Use device MAC", try to disable it if it is automatically on.