Hi @araether0 
Welcome to the Canvas Community. Your subject line states you can't add more emails, but your message the emails are not working, which could mean something else. To address what's asked in the subject, let's make sure you're in the right place (it sounds like you are), which is under Account and then Settings, as outlined here: How do I add contact methods to receive Canvas notifications as an instructor? (You did not indicate if you are a student or an instructor, but in either case the methodology is the exact same.) If you find you cannot add additional email addresses there at ALL, this may be something to bring up with your local technical support, as it is entirely possible that they disabled this feature administratively.
As for the email not working, let's say you did add an email, and just simply are not getting notifications sent to that email. For each contact method that you add, Canvas has its own set of notification preferences. From the same Account menu, select Notifications, as covered here: https://community.canvaslms.com/docs/DOC-13111-4152719738 As that online lesson shows, for each email address that you add, there will be a column added on your notifications page, allowing you to set unique notification preferences for each and every contact method. See if that makes a difference for you.
I hope this helps a bit, Ashley, or at least allows you to narrow the issue down.
