Thanks Shannon. I did swap the battery when I swapped the logger. I am using the matte finish panel. Also, I went to the EnviroDIY knowledge base parts list and clicked the link for the panel there. The link sends me to the old panel on Adafruit rather than the new panel we are using.
I believe everything is plugged in to the correct ports on the Mayfly but we can double check. I’ve noticed those new panels are difficult to plug in, so maybe something happened. there. I can also swap out the 2-pin cable connecting the panel to the Mayfly to see if that is the issue. Thanks again.