I was powering it from the USB port on my computer. I thought is was a power brownout problem so I built a battery powered regulated 5.0v supply with and lm317 which could easily deliver 1amp. Things seemed to work better, didn't concern myself with the occasional crash during development.
My code is a data logger which sends 25 bytes of data over the wifi every 5 seconds and needs to run for days. I could get the board to run for a few hours but it would always eventually crash. The crashing is now more frequent, I am lucky to keep it running for 30 seconds now. Most of the time now as soon as I ask my PC to connect to the WIFI network it immediately crashes. The board seems to have degraded an now hardly runs. I have ordered a new board and hope it works.
I have used both client and AP server mode. I am now in AP server mode. I am using the blue led as a mode light to show me what part of my code is executing. When it crashes the led goes to a very dim continuous on state. I Have a debug version of the code which I can run with the serial monitor when connected via USB. It has the same behavior and when it crashes there is no diagnostic displayed.
Has anyone else had this problem?