@PinkSpider Hey, I also had this problem, and after all the suggested solutions failed to solve the problem (but somewhat pointed to what might be the issue) - I somehow managed to find the issue and resolve it.

The TL;DR: The bulb cuts off the initial WiFi connection with the phone too soon - the Tapo app can't transfer the needed info to the bulb to complete the pairing process. So one has to go through the pairing process (finding and selecting the SSID and inputting the WiFi pass) quite quickly.

if one manages to speed through the pairing process - it works every time (well, at least for me it does).

You can read the rest in my lengthy post here, if you wish:

https://community.tp-link.com/en/smart-home/forum/topic/274340?replyId=1182634