With MQTT I Cannot program electron unless I place it in safe mode

[kostbill]

I tried to re program the keys, as seen here:

Photon Not Connecting to Cloud [SOLVED]

It started with this particular Photon, where it was working just fine. Then one time after Flashing it via the Web IDE, it almost connected and then started flashing blue. After this, no matter what I did, it would go into listen mode on boot. So I then set up the Wi-Fi SSID and credentials etc. using the CLI. Now it flashes green and then flashes cyan, but never connects to the cloud. I have another Photon right next to it and it connects to the cloud instantly. Next, I flashed the Blink and …

but still nothing.
I cannot program it and I cannot ping it from the Particle console.

Any ideas?