I purchased 10 of these plugs and was only able to connect 3. After the first three, the other seven fail to connect to WiFi. I've tried resetting the plugs and after I enter my WiFi password for the plug during the setup process, the light turns from orange to flashing blue but it never completes. Here is the interesting part; if I restart any of my 6 access points, the device I just tried pairing becomes visible on the network, the TP-Link app and works. However, it drops any existing one off the app and the network.
If I attempt to re-pair the one that got dropped from the network, it becomes visible again on the network if I restart my access points but drops another. Like musical chairs :D
It's a vicious cycle and looks like it does it when more than 3 devices are connected and configured at a time. Thinking it was my network, I disabled all AP's and used only one. However, same issue. I then created an isolated WiFi network and still have the same issue. This isolated network was with both completely different network hardware and a different network subnet.
To take it a step further, I went to my shop and tried it there. Same exact issue. I can't get anything more than 3 smart plugs at a time. As soon as I add a fourth one, a previous one becomes greyed out. My network at home, at the shop, or even my isolated network test-beds have more than enough capacity. I can add any other device including additional TP-Link devices. For example, I have 6 wall switches from TP-Link that I was able to add without issues and they all work. None of those drop. I also have other brands of switches and plugs that I am able to add without issues.
Any ideas? Looks like I am on the latest firmware for these devices too.