Hello Ladies and Gentlemen!

I am reaching out because I am having a problem with my new tplink camera and although I know there is a different section in the forums for that; I found out that the culprit is my (rock-solid until now) EAP225!

So the backgournd and details first:
My home network is being served by two routers and an access point.
First (front) is my ISP's gateway modem/router which is handling my VDSL line and operates in bridge mode.
Hard wired to it there is my dd-wrt router (Cisco) which acts as my firewall and my DHCP server.
Finally my tplink EAP225-V3 is also hardwired to my dd-wrt router and provides WiFi to all my wireless devices in (and out) of my house.

Up until now I also had an OEM IP camera connected to my EAP225 working fine both when accessing it from within my home as well as from the outside using the relevant app on my smartphone.

And then I bought a tplink Tapo C200 to replace it...

The Tapo C200 needs to be configured via the Tapo app at first in order to ba accessible/functional. Every time I tried to connect to my home wifi (coming from my EAP225) the app would show me the "Pairing failed" error message.
When setting up the camera there are three steps:
1) Connect the tapo app (smartphone) to the camera's wifi.

2) Select the wireless home network for the camera to join and give the password for it to connect.

3) Pair the device.

The first two steps were always successful whereas the pairing always failed! The camera was always getting the proper (static) IP from my router, but for some reason the last step (pairing) could not be done. Therefore the camera was NOT working at all.

I tried everything I could think of (and read). Different smartphone, tablet, passwords, wifi channels, disabled firewall completely, app permissions (you name it) and there was always the same error.

Finally, I turned on the wifi on my dd-wrt router and VOILA! The Tapo C200 is now working fine!

To sum up; when bypassing the EAP225 completely and using the wifi from my dd-wrt router everything is in order.

What settings should I be looking into?

Thanks in advance.

PS
I knon it works but I rather have my EAP225 be the only WiFi AP. There shouldn't be a need to have my router's WiFi on as well.