I have a number of smart plugs around the home, two on the home wifi and two more connected via a second router in my workshop to the same gateway. These four (a P100, two P105's and a P110) all work fine. Recently I moved another P110 plug from a seperate location onto this home network but have been unable to get a connection made. I did a full 10sec green blinking factory reset but still with no luck.
In the Android app the process starts ok: 

1. The plug flashing green and orange

2. I hit the + sign in the app to add a new device

3. The "Power Up Your Tapo Device" screen loads and I hit the "Already Orange and Green" button.

4. The screen dulls and the phones "Connect to device?" popup loads and I select the Tapo_Plug_XXXX that is stated.

5. It then says "Connected" in an overlay at the bottom of the screen and the blue screen "Tapo is looking for your device" is displayed.

6. After a short period the "Unable to find Tapo device" screen loads with the option to try again. This screen is the wifi screen version shown in Case 1 of the user support web page.

If I go to my phone wifi connection I can see that it remains aparently connected to the Tapo_Plug_XXXX 

The phone is a Samsung S10+. I've tried a different phone (same model) and its not working with that one either.

Any suggestions?