@TristanDien 

Check if the light strip's Wi-Fi appears on the connected network list and remove it if it does. When you attempt to reconnect to this Wi-Fi, you may receive a message indicating that it doesn't have an internet connection, prompting you to switch to cellular data. If that happens, be sure to select "No." Then, check if your device can connect to the smart light strip's Wi-Fi. How to remove existing wireless network profile on Android&iPhone

Your situation is rare, and it is hard to determine the cause of the problem at this time. Since you've already tried to use several mobile devices, i would recommend requesting a replacement for this light strip, see if the issue persists. To proceed product warranty, you may contact the retailer or local TP-Link support.