Lily 2 not tracking heart rate

I received my Lily 2 for Mother’s Day and LOVE it.  However on July 4 it stopped tracking my heart rate and sleep, with no change to the fit of my watch.  I was able to reset it by attaching to charging cord (even tho battery was not low) but it happened again today.  I’m on software version 5.2.1.2.  I am a bit frustrated that it is so new and starting to have issues.