Hi @Liverpool20 

Thanks for the reply! I think I could sort out the DHCP issue myself, by plugging the WAN uplink cable back to LAN port of AX1500. The AP mode was set by choosing the operation mode from the web interface, after which the router reloaded its firmware and rebooted itself... 

About the model: both model numbers are present on the box: AX1500 and Archer AX12. On te administration webpage, on the top left part it says "tp-link AX1500 Gigabit Wi-Fi 6 Router", while on the Firmware Update menu it reports "Hardware Version: Archer AX12 v1.0"

It seems that the original issue is still present albeit it looks like it relates to something with the WiFi infrastructure design. There were 3 AP-s in the building I have to cover with WiFI infrastructure, to obtain a reasonable signal strength everywhere. One of them is the Internet router (LINKSYS) the other one is a TP-Link Wireless N Access Point WA801N, and the third one was a tp-link Archer C20 AC750 Dual Band router used as an AP. The plan was to replace the latter with an AP with GbEthernet LAN port (the AX1500) as the internal LAN infrastructure is now pure GbE and the Internet bandwith was also upgraded to 300Mbps/300Mbps. ALL the AP-s were set to use the same SSID and password, and were operating on different 2.4/5GHz bands, configured and controlled manually. Everything worked fine as the WIFI endpoints would roam automatically between these AP-s. After I switched the Archer C20 to Archer AX12, the problems described started showing up. 

Now I switched back to the original setup, but paralelly I am operating the AX12 with different SSID than the others on different WIFI RF bands. I am testing it with one tablet and smartphone. This way the problem disappeared: these two endpoint can use the AP without problems, there is no dropping off. There are some wierd log entries in the system log which I do not understand:

2023-08-04 00:07:13 Led Controller INFO [1859] Start to run WAN1_OFF

2023-08-04 00:07:13 Led Controller INFO [1859] Start to run WAN0_OFF

2023-08-04 00:07:13 Led Controller ERROR [1859] Config importing failed

2023-08-04 00:07:13 Led Controller DEBUG [1859] Failed to read LAN_ON

2023-08-04 00:07:11 Led Controller INFO [1859] Start to run WAN1_OFF

2023-08-04 00:07:11 Led Controller INFO [1859] Start to run WAN0_ON

2023-08-04 00:07:11 Led Controller ERROR [1859] Config importing failed

2023-08-04 00:07:11 Led Controller DEBUG [1859] Failed to read LAN_ON

But the question still remains: how can I replace the Archer C20 with AX12 to use the same SSID as the other two AP's?

  @Tschabha 

You could try updating the new firmware Archer AX12(EU)_V1_1.0.6 Build 20230616 to see if it helps:

Download for Archer AX12

I am also facing same issue with my Ax12 router when using as Access Point. Tried connect the cable in both wan and lan ports , behaves the same way. Client devices fails to get IP address. Tp link should provide a fix via firmware upgrade

  @Tschabha 
I also have the same problem. I have 4 units of AX12 in AP mode and all experience the same problem. Sometimes the devices can connect but the connection drops. Most of the time the connecting devices get stuck at obtaining an IP address. I also have an Archer A8 in AP mode that works properly. 

Did you already contact or email TP-Link support about this problem?

  @Tschabha 

Hi, same issue in here, anyone any results?

I have an idea/workaround on how to get this to work but it woul imply migrating configuration from main router to this one (I don't want to do that and I'm sure neither will you): using the AX12 as the DHCP server.

Hope TP-Link solves this issue soon or I'll be returning the device!! I suggest you do the same to put some pressure.

  @Tschabha Estou com omesmo problema e usando a mesma situação, com SSID diferente, infelizmente.

I've contacted TP-Link support and they told me that they are trying to recreate the problem in order to fix it and it may take some time. Perhaps all of you can also email TP-Link support to let them know that you also have problem with the AX12 in AP mode