Email throttling is the practice of intentionally limiting the amount of email you send through a server in a given period of time. Throttling can refer to what ISPs and mailbox providers do to your emails when they receive them, or it can refer to the practice of setting your own email out to send gradually.
Receiving mailboxes (ISPs) often have a limit on how much mail they can receive during a specific timeframe. If you’re sending them too much mail, or sending it too fast, they can choose to defer mail in a process known as throttling.
What are signs that you're sending too much email and being throttled by mailbox providers?
- Deferred messages instead of Delivered
- Blocked messages, including blocks that mention "too many connections"
How can you address throttling by mailbox providers/ISPs? The best way is to schedule your emails to go out gradually.
How to Throttle your JangoMail Messages
You can set your campaign to throttle in Message Settings or via API options in SendMassEmail.
In your message, click on the Schedule tab. Mark Yes next to Enable send throttling? and select the desired values.