Single Red blink on Photon 2

[JSchrempp]

We have a very small test app running on a Photon 2. It has a LoRa radio. When it receives a LoRa message from another device it will respond with a LoRa message. We run with system threads enabled and system mode semi-automatic. The LED normally breathes white. This all works great, except in one case.

When our breadboard is resting on a metal window sill the code works, but after sending the LoRa response the LED blinks red once. Not the SOS code but just once. The device does not reset. We're not sure what a single red blink means.

[rickkas7]

That's not a standard blink color code during normal operation. Is there anything on the USB serial log? You may need to enable logging:

SerialLogHandler logHandler(LOG_LEVEL_TRACE);

If trying to connect or reconnect to the cloud, a red or orange blink can indicate a problem handshaking, which sometimes will resolve by itself, because the error could be connectivity related.