Email certificate error

When I try to send an email through my Outlook client using my Homestead email, I keep getting this message: "The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect. Do you want to continue using this server?" When I press yes it seems like sometimes the email sends and sometimes it does not. 

When I click View Certificate I see the below data. I notice this problem started around March, when the new certificate was issued. How do I resolve this? Sometimes my emails are going through and sometimes they are not. The current smtp address I'm using is smtp.homestead.com, port 587, STARTTLS