Comcast blocking emails from church email domain

Hello - we've had a number of notices from comcast email users that our church emails from plcchurch.org domain are not received.  I am a comcast residential user and tested a number of times, and this is the case - emails are not coming through.  I do not have any email rules set up, nor have I marked this domain as junk/spam.  I'm wondering what I can do to get this unblocked for church members?  Thanks.