Room AC AR09KSWSBWKNZE 2018 Wifi adapter how to reset?

Hello All! I have 2 room Ac units, AR09KSWSBWKNZE, both identic. I had them connected to Smart Things, working well. My router get busted, so I had to buy a new one. After installing the new router, I connected the AC from living room, works well, also with Bixbi, I’m happy with it. Well, at the second one, identic, when I try to add it on Smart Things, I press the remote Timer buton, AP is coming, then message with “getting ready”, then image is moving on white background, it says connecting, the second dot it keeps spinning around, the phone is connecting with it, (I can see there that is the password from the old router) but this is all that it does, I cannot connect it with the new router. The ST app it keeps trying for few minutes, then aborts with error 31-162. It give a help buton, where I’m advised to reset the Wifi adapter by pressing “-” and SET key. It bip once after 5 sec, bip again once the same after 30 seconds, and then bip once the same after another 30 seconds but nothing happens. I turned on /off, I unplug it, still nothing.

If your Wi-Fi router has 2.4 and 5Ghz for the same network name, try disabling 5Ghz and then try to connect.

Thanks for the advice, I tried, still not working. If I scan the wifi network, I can connect with the phone to the AC, I can see the password, but the Smart Things app is not finishing the installation. The funny thing is that I have 2 units, identical, I bought them in the same time, the other one is working fine. Also, I tried the combination with the “-” and “SET” buttons, still no luck.