@Kevin_Z 

Thanks a lot for your prompt response!

Here we go.

1. I'm still connected to the 5GHz. And no internet connection.

2. Thanks for the instructions. I've attached the snapshot with some markups. Hope that it will be clear. Sorry for the Russian.

3. I'm not sure that I ever tried to do this.

4. The firmware is relevant. I've installed the latest available. 

Here are some comments about the snapshot:

- connection lost while watching youtube;

- ping 192.168.0.1. The result - Request timed out;

- I have connected to the 2.4GHz. The internet is available;

- I have reconnected to the 5GHz. The internet is available.

Thanks for your attention to this question.

I hope that the solution will be found.

Thanks in advance!

@Kevin_Z 

I am having the same issue as well. I use a Macbook pro-2015 and through my searches online for the answer many of the forums have said that Apple products overwork the router due to which it gets heated up and stops. 

But I have tried everything that other forums have suggested. Like, adjusting the placement of the router, adjusting the antennas. 

I recently bought this Router as an upgrade to my previous D-link router which was a single band router. 

I connect only 2 devices to the 5Ghz band and with time the internet gets slow and choppy. There is no problem with my ISP cause the internet speed is consistent when directly connected. 

I have also checked interference, changing channels, and everything that people have suggested but to no improvement. Does that mean that my router has crashed or I have gotten a faulty piece?

I am from India and use the ACT 100Mpbs connection. When connected, the 5Ghz connection shows very fast speeds close to 100Mbps but with time it gets slower and after about 15 min of video streaming or online live classes, the speed completely drops to a point where I'm no longer able to access the internet at all. The 2.4Ghz band works for some time but even that gets slow and crashes to a point where I have to restart my router again to get consistent speed which I cannot do when I am in the middle of a class. 

I have upgraded the firmware to the latest version but still, experience the same issue. Can it be possible that my ISP connection is not compatible with the router?

Please let me know what I can do to have a stable long-lasting connection for the 5Ghz band