@Amarjyoti did your slow 2.4ghz WiFi problem get solved? Am having the same issue

@Amarjyoti 

Hi, were you able to resolve this issue? I am experiencing the same/similar issue:

Powerline connection between adapter and extender is strong (according to tplink utility it is around 300Mbps).

5GHz Wifi signal is strong at around 60Mbps.

The 2.4GHz signal is terrible, at 0.05Mbps. 

This has only started happening in the last 2 days, before that I was getting 50/60Mbps on 2.4GHz.

I need the 2.4GHz as I am using it to extend the existing network in the house which is 2.4, and my parents wouldnt have the technological knowledge to change connection as they move around in the house.

Things I have tried:

Bouncing my router, the adapter and extender, both independently and together.

Resetting the Extender.

Updated firmware on extender, now on 3.24_751012_181123_901

Tested it with cloned network from my router and without cloned network.

@Amarjyoti  Hello from Kansas.  Did you ever get the slow 2.4 resolved?  Same issue here.  I got the newest AC1900 to replace a 8 year old Asus which performed much better before it died.  Thanks, Rick

@Amarjyoti 

Hello, I have same problem with my C50 router and Ac2100 modem router (to try as a access point).

I am using internet from CPE210 to CPE210 with another brand modem:

Modem - wired to CPE210 (Accsess point) -wifii - CPE210 (Client) - wired access point 2.4 (different brand)  and I don't have any problem.

It works fine. At modem side I have 34 Mb internet speed and at the other side it is nearly same.

I decided to change my old modem and old access point to work with 5Ghz. I bought AC2100 and C50. As a modem AC2100 is ok. At the other side when I use C50 as a access point 5GHz is ok but 2,4 Ghz is 1/4 of real speed. I tested it with many devices. Also wired speed is ok too.

Then I changed my AC2100 modem as a access point and remove C50 to try with it. It was same, 2,4 Ghz speed is 1/4 of real speed.

And the strange thing is: To try I take C50 to my office everything was fine at 2,4 Ghz and 5 Ghz. 

I did't understand anything why 2,4Ghz speed is low at my home with both of c50 and AC2100 and why my old different brand access point work fine at 2,4 Ghz.

We now have exactly the same problem. Speeds on 5Ghz are great (300+) and operation is flawless, but 2.4Ghz is getting horrible with speeds dropping to 2-3 mbps, patchy network or no internet access at all. In addition, it tends to kick out some of the devices connected to 2.4, which is especially annoying when 99% of smart home devices work on 2.4Ghz. 

Judging by responses, I'm not alone so there is a fundamental problem with this equipment. 

@alenalien38 Unexpectedly it worked and its working fine since then lol