Argon keeps going offline after I flash it

I have code I created on the Web IDE. I flash my part and run the code. I can see the I2C on the logic analyzer looks correct and I can see that my DAC output is updating. If I then make changes to the code and download, or even try and flash the exact same code or try and run another .ino file (that has worked all day) the part will not flash. I get the following:
“Device not discoverable or is offline”

I then hold mode and reset together, release reset, wait a sec then release mode and I can then flash again but of course then I am back to square one and have to go thru the whole process again…

What is going on???

solved…
SYSTEM_MODE(MANUAL)

shuts off WiFi!!!

Beware.

You have to maintain all connection logic yourself if you set system mode to manual, read more here: Device OS API | Reference Documentation | Particle