Here are three of the most common reasons an e-mail may get "bounced" –
there is a typo in the e-mail listed in a contact’s record
the e-mail address no longer exists or is inactive
the e-mail client has rejected or quarantined the e-mail and flagged it as Junk/Spam
Regardless of the reason, when an e-mail returns to 'Donor Management' as “bounced,” the 'Does this e-mail address receive emails?' will automatically be toggled "off" and display a grey 'x'.
Your system automatically sets an e-mail to not receive communications after bouncing because e-mail clients are sometimes more likely to reject an e-mail if there are already “invalid” (or "bounced") e-mails listed as recipients.
If you try to send an e-mail blast to 100 contacts and 10 “bounce”, the likelihood that more e-mails will "bounce" (that did not do so previously) is higher if you try to re-send the e-mail to those contacts.
If the e-mail address "bounced" due to a typo, or you have an updated e-mail address to replace an incorrect one, you can toggle back to that blue and white checkmark from the contact's record. This should allow that e-mail to receive messages from 'Donor Management'.
Note: Each e-mail address reflects as “bounced” independently from any other e-mail address attached to a contact’s profile. So, even though one e-mail address on a contact record may have "bounced," if a secondary e-mail is listed, it may still have received the original message without issue.