Those voltages sound reasonable, so the next question is, what does your input circuit look like?
I’m not familiar with the ESP32 processor in total, so don’t expect me to have any deep knowledge of how to set up the software libraries you’re likely to need in addition to emonLib.
What you are looking for is what input voltage range does the ADC input expect, and does your hardware supply a signal that has a “no input” voltage that sits close to the middle of this range, and does the range extend from that centre voltage at least half a volt either side?
If all this looks sensible and correct, bear in mind emonLib is written specifically for the Atmel ATMega 328P, not the ESP32, so there are other libraries and things you must do to read the input voltage and get a number in the software so that emonLib can use it. EmonLib won’t do it unaided. Searching here for ESP32 should find a few threads which might help, like this one which explains the process of setting up the ESP32 and what to look out for reasonably clearly: ESP32 Problem with YHDC SCT-013-000, or there must be other on-line tutorials.