If you've resubscribed a guest on their timeline using the checkboxes at the bottom of Edit Profile but they subsequently are not receiving emails, please contact Sendgrid support to check the status of the guest's email address with regards to the suppression lists within Sendgrid
https://support.sendgrid.com/hc/en-us
Below is linked an article that explains the 9 different email events:
What do the SendGrid statuses mean?
Scroll to the very bottom
