in the log file, there is indeed an error indicating that on day 263, the data being read off the serial port is gibberish. you should verify the connections between the Pi and the Shake board and confirm everything is properly connected.
v0.19 has just gone out, as well, reboot your unit to pick up this update, perhaps (though unlikely) this could have a positive effect.
it is caused by something that is not working as it should between the blue Shake board and the Pi board underneath. This is also supported by this other line in the logs:
2021 265 05:15:30: Unable to read Firmware version number off of Serial Port /dev/serial0 after trying for 15 seconds, cannot continue!
2021 265 05:15:30: Is the Pi computer connected to the Raspberry Shake Board? Please confirm and try again.
which confirms the connection issue.
It is quite a strange situation because the Shake managed to connect successfully to our servers before all of this happened. To summarize, the Shake is able to reach our servers, but since the data flowing from the sensors is corrupted, no connection is established, and no data is uploaded.
Here are the solutions that I can suggest:
Substitute the current Pi board with another one that you have around to see if that element was the cause of the issue.
You can send back the Shake to us, and we will look at it in person and then send it back to you in nominal working conditions. If you choose to do this, please send an email to [email protected] and they will guide you through the process.