Video doorbell Pro with Plug in Transformer adapter.

Hi, I am currently experiencing regular bouts of being offline with my video doorbell Pro. It is currently supplied via a Ring plug-in transformer, however, my last Voltage reading was 3177.0mV and I believe I need 3900.0mV and on the device health it shows poor and reading between the lines Ring state this is normally due to a poor circuit/power source. Well it is plugged in less than 20 feet away from video doorbell and it is plugged into a house that is only 20yrs old so I doubt I have an issue there. Am I correct in thinking this may be the adapter that is at fault? I hope not as it took ages to get it in place and hide the power cable correctly. Anyone else having this type of issue?