Missing Emails from "groups.io"

For the past few over half of my emails from the several "groups.io" mailing lists that I belong have never made it to me.  This is the case for both my Thunderbird platform and also the web based email.  I know of a friend in Connecticut who is experiencing the same.  Anyone else?  Also can someone (if the read the forums) from Xfinity chime in?

Thank you

Keith