RT-AC88U: 2.4Ghz suddenly won't connect unless I make it an open network?!

[iMe]

ASUS RT-AC88U

All of a sudden, 2.4Ghz won't connect to the internet unless I make it an open network! I found this a problem after hours of troubleshooting and a factory reset when I noticed that the home devices lost their internet connection.
When its encrypted, a device would take a long time (~60 seconds) for it to connect to the network and when it does, it will get a local IP but there is no internet connection (Chrome: "DNS_PROBE_FINISHED_NO_INTERNET") and can't access the router page (Chrome: "192.168.2.1 took too long to respond").
When I remove the encryption and make it an open network, everything would go fine, except that browsing the router page is extremely slow and laggy for some reason!

5Ghz band still works 100% fine even with the encryption.

Few things I tried but still no luck:

• I'm currently on the latest version of Merlin, I did try the stock firmware after a factory reset.
• I did try to "forget" the network each time I try change something on the settings.
• Renamed the network and changed the password.
• Tried both WPA2-Personal and WPA-Auto-Personal.

Any suggestions?

 

[iMe]

Anyone?

 

[cdkao]

ASUS RT-AC88U

All of a sudden, 2.4Ghz won't connect to the internet unless I make it an open network! I found this a problem after hours of troubleshooting and a factory reset when I noticed that the home devices lost their internet connection.
When its encrypted, a device would take a long time (~60 seconds) for it to connect to the network and when it does, it will get a local IP but there is no internet connection (Chrome: "DNS_PROBE_FINISHED_NO_INTERNET") and can't access the router page (Chrome: "192.168.2.1 took too long to respond").
When I remove the encryption and make it an open network, everything would go fine, except that browsing the router page is extremely slow and laggy for some reason!

5Ghz band still works 100% fine even with the encryption.

Few things I tried but still no luck:

• I'm currently on the latest version of Merlin, I did try the stock firmware after a factory reset.
• I did try to "forget" the network each time I try change something on the settings.
• Renamed the network and changed the password.
• Tried both WPA2-Personal and WPA-Auto-Personal.

Any suggestions?

I"m having the same issue on my ASUS RT-AC87U. Please help if you have a solution.

 

[iMe]

I"m having the same issue on my ASUS RT-AC87U. Please help if you have a solution.

I just asked for a replacement from where I got it from (Amazon) and the new one I received seems fine.
So that confirms the only logical theory that this is a hardware issue. The 2.4Ghz chip could have gone faulty due to heat or something... so just in case I started using a USB fan to cool the router down. The CPU used to be ~80C and now ~50C.