Outlook not sending Zoom email invite but showing up on Outlook calendar

Our 3 person company uses Outlook as primary email with Zoom plug in. When we schedule a Zoom meeting, the email is showing up as sent, but the recipient within the company (another Outlook user) isn't receiving the email. However, the meeting is showing up on their calendar. There seems to be no problem with invitees outside the company receiving the email no matter what email they use. 

I realize this is likely an Outlook issue but thought I would try here for a solution as well.