The I/O System view has a bug that it is currently not providing which channel on the on-board analog input channels is the issue (fix should be out very soon).
Regardless, it is most likely that one (or more) of your on-board WX's is configured for 4-20 mA current, and it is missing its signal. Either wire it up (and getting at least 4mA), or if it's unused, reconfigure it to be voltage (this is the default).