Emails Not Received

Yet again I am having trouble with my emails not being received by multiple people including people who have received my emails in the past and ones I am responding to. I have had this trouble in the past and then someone from Homestead resolves it. I do not receive any error messages that the email was not sent, only contacting people in other ways and through my personal emails am I finding that they never received emails through our nonprofit email account. This is getting extremely frustrating, and I keep worrying how many of my emails have not gone through. I believe this has only been a problem for the last few weeks. Some of my emails have gone through, but many are not. Help!