After the last reboot the connection lasted for about 5 days. Which is still way too short in my opinion. 

I put my answers between your questions:

Kevin_Z wrote

@broxtor 

 

Sorry for the trouble caused here, we can do some analysis and try to fix it. 

 

1. What is the led status of the Archer AX6000 when 5GHz lost connection?  Does wired connection and 2.4GHz wireless connectio work well?

 The led is continuous red. Bot 2,4Ghz wireless and wired network keep working. When the 5Ghz is visible I can connect to it, but no internet traffic is possible. I do need to add that I don't have anything connected to the WAN port of the router. I have a modem/router combi from my ISP. I have that connected to a LAN port on the AX6000. I didn't want use the WAN port since I need other IP ranges then. 

2. When the 5GHz is visible, any error message pops up which indicates that you cannot connect to it? 

On my android tablet I get the wifi icon with an exclamation mark saying that I do have connection, but no internet.

 

3. Have you ever tried to forget the profile and reconnect the 5GHz to give it a go.

 Yes, I did that. But no improvement.

4. Try to modify the wireless settings of the 5GHz to optimize the wireless performance, like wireless channel and channel width. Channel 36/40/44, channel width 40MHz. 

 Will do that.

5. Besides, may I know have  you enabled the QoS or parental control feature on this router? And who is your ISP? 

I did not touch the QoS and parental control settings, so they're on default. My ISP is Telfort.

 

Thanks in advance, and have a nice day. 

@broxtor I actually have the same problem with the 5ghz wifi. I bought the ax6000 today and 5ghz wifi stops working after an hour or so. I rebooted the router and it works again for minutes or an hour. I can connect to the 2.4ghz network, that one doesn't seem to go down. I can still see the 5ghz network in android and in windows, but when trying to connect to it, it says 'failed to connect'. 

@broxtor I have the same issue. I don't have any issue on 2.4ghz or wired but on 5ghz i lost internet access after some hours. 
I'm trying to change some parameters to see if I can fix it myself. I hope tplink will release a new firmeware to fix that, i didn't have any issue like this withvmy previous ac router.

Finally i fixed the issue by fixed the chanel and the chanel wide to 80 mhz. When I set to 260mhz i have the issue like othet and I described.

so, probably on auto mode, when it switched to 260 I lost it. 
note : I didn't have any issue on 40 mhz too but the connection is very slower.

@Kevin_Z 

It seems to be a bit more stable, but every once and a while it still stops working. 

The LED I mean is the square one on top of the router. 

I did notice that when the 5GHz wifi stops working it is also greyed out in the user interface. I cannot select it then and change settings. I first have to reboot the router and then I can get back in the router and change settings.