@Tamas71 that is weird, one thing i noticed though is that you mentioned that you have 2 lan cables coming from the modem, one going to the WAN port of the AX50 and the other to a TV set top box .......

@Tamas71 try setting the MTU Size to 1448 and observe if it still drops the internet. other than that, it might be the lan cable, make sure to use a cat6 or better lan cable connecting the modem to...

my TP-Link devices > Archer AX50 router mode > TL-SG1008 switch > Archer C24 AP mode > Archer C54 AP mode was planning on adding an Archer C64 but thinking of going to mesh I'll put on my conspiracy...

@ryan9379 wallmount the AX50 for better heat dissipation lower the "transmit power" for either the 2.4 or 5Ghz wifi signals, I have my 2.4Ghz set to "low" and 5Ghz set to "High" other than that, you...

@colefamous check/change the LAN cable going to the C54 if possible and also just for isolation relocate the C54 power adapter to a different outlet. you can also set the wireless channel on the C54...

@DdLee Try to use a PC/Mac to configure the AX5400, the Tether APP might not have the options needed for Unifi/Maxis ISP to properly get to the internet. Checkout the review of the AX5400...