Error 900 is a "catch-all" error code for an issue that the system has not encountered before or does not have a specific classification for.
You should never get a 900 error. This code is reserved for unhandled exceptions in the software or hardware communication. If this error appears, it will almost always be accompanied by a modal pop-up box containing a large block of technical text (a stack trace).
Because this is an "Unknown Error," this technical text is the only way for the development team to diagnose exactly what happened in the system's logic at that moment.
Since this is not a standard user-serviceable fault, the priority is capturing the data before it is cleared:
Capture the Text: Do not close the error message immediately. Take a clear picture or screenshot of the tablet screen, ensuring all the text in the modal pop-up is legible.
Email Support: Send the picture/screenshot and a brief description of what you were doing when the error occurred (e.g., "happened right as I clicked Start on a 3-product mix") to support@praxidyn.com.
Basic Recovery:
Reboot the Mixmate hardware.
Restart the Mixmate App.
Check for any Android Updates as described in Error 401, as outdated system components can sometimes cause unknown software crashes.