Email Sending & Troubleshooting

Please select from the below article(s):

• ○ Will Mailgun retry my failed messages?
• ○ Internationalized Domain Names (IDNs)
• ○ Reply-To Addresses
• ○ Why did I receive the error "Relaying Denied" (or some variation thereof)?
• ○ Finding an email's message-ID
• ○ Why would an email display "On behalf of"?
• ○ What is the difference between the “From” and “Sender” headers in an email?
• ○ Why does delivery become slower after submitting a lot of messages?
• ○ How can I send the same email to multiple recipients?
• ○ How can I delete emails that are queued for delivery?