@arkamaden 

Blinking blue usually indicates the plug is trying to connect WiFi. Have you updated your wifi name or password?

Try to unplug the P105 for a while, like 10-15 minutes, then plug it back in, wait until the device completes rebooting, then try to factory reset it again. How to factory reset the Tapo smart plug

If plug's led indicator does not show any changes, you may try to re-add this device in the Tapo app, see if the setup can go through. There is a small probability that the device's LEDs are malfunctioning and do not correctly show the status of the device, and it is possible that the device has been successfully reset. If the setup also fails, you may contact the retailer or local TP-Link support to proceed with the warranty.