Subscription Email Not Received By All Recipients

I have a subscription set up for four individuals using their specific email addresses with a semi colon and space between each one.  For some reason the email is only being received by two of them and I can't figure out why.  Those missing the email have looked in the company "Junk Email" folder to make sure it isn't getting flagged as spam or other "junk" and I've confirmed their email addresses twice now.  Has anyone experienced this before and/or know how to fix this? 

Thanks!
Rachel Miller

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Rachel Miller
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