Logger not transmitting data to website

That happens occasionally when the connection between the Mayfly and the online time server gets terminated before the entire timestamp gets transmitted, resulting in an incomplete timestamp, and the Mayfly code has some smarts to check whether the timestamp it received is a valid, reasonable date.  If you ever get this error, you can just restart the logger, since (with the sketch you’re running) it will always try to contact the time server upon startup.  Once your board gets a valid timestamp, it will set the clock chip on the Mayfly and it shouldn’t forget that time unless you remove the CR1220 watch battery (or the watch battery dies after a year or two of sitting in a Mayfly with no other power source).   Once the clock on the Mayfly has been set, in the future when you restart your Mayfly, you’ll see text on the serial monitor saying what time the Mayfly thinks it is, then it’ll say it is contacting the time server, and then it should say something like “clock is already within 5 seconds of the correct time”, meaning that no adjustment to your clock was necessary.  If you aren’t getting a successful timestamp from the online server, then it probably means your cell signal is weak (or non-existent) or there’s an issue with your SIM card.  Note that when you’re first using a Hologram SIM card with a Mayfly, it can take up to 2 minutes to connect to the time server the first time, and occasionally it can require 3 or 4 reboots and 2-minute waiting periods to successfully connect when using a new card for the first time.  Once you’ve successfully made a Hologram connection, subsequent transmission will only take about 8-10 seconds.