We preformed an email send a few hours ago to around 9,000 people and all of them are still sitting in "Send Email". Is there a reason why the email would not be delivered to a single person hours later? I ran an email performance report to confirm as well and the "delivered" column does indeed say "0".
Thanks in advance!
They can sit in pending for 24-36 hours if the recipient mail server is not accepting the message and the Marketo system is attempt to retry multiple times. If they haven't moved to bounced or delivered after 36 hours, you should contact customer support; likely something went wrong while the email was being built.