We are aware of issues delivering email to several external domains including messages sent to @yahoo.com. We are actively working to address these issues and we apologize for any inconveniences that this issue has caused. Due to the nature of the problem we do not have a time line of when the issue will be resolved.
If you are experiencing the issue you should receive a notification that delivery of your message has been delayed, or possibly failed. A delayed message means that the system will continue to try to deliver the message, however a failed notification means that the email has failed to send completely.
We will notify all users when the issue is resolved. Thank you for your understanding.