Why emails may be delayed


It is a common misconception that email delivery is instantly completed after you hit "Send." Email is designed to be sent from Mail Server to Mail Server until it reaches the ultimate destination, with no guarantee on how long it will reside at each intermediary stop. 

There are a few reasons why an email may be delayed, some of which are a delay by ActiveCampaign and some on the receiving email client's end. Learn more about how fast emails will hit the inbox.

Delays on ActiveCampaign's end

Delays on ActiveCampaign's end can be due to the following:

  • Slow or overloaded mail servers
    This overload could be due to volume, combating spam, or other tasks.
  • Reputation-based deferrals  (giving us 4xx responses saying "rate limited").
    These are temporary errors, and our systems will try sending the message again. We continue to attempt to send these messages for up to 72 hours until the message is delivered. If a message is continuously deferred for 72 hours, we will discard it.
  • Mailbox Providers and ISPs have standards regarding how many connections we can have open to them 
    They also have standards for how many messages per connection we can send simultaneously. There are times when volume exceeds these thresholds, which can cause the mail to be queued.
  • Pre-send processing
    If there is a technical issue with sending the campaign, that can lead to delays. Examples can be a complex segment, large lists, etc.
  • Compliance campaign approval process
    All first-time campaigns go through an approval process. This ensures that your campaign is within our Terms of Service and meets industry standards. However, even seasoned users may find that their communications must go under a manual review. Learn more about the campaign approval process.

Delays on the receiving side

Delays on the receiving side can be due to the following:

  • Slow or overloaded servers
    Again, this can be due to too much incoming mail, filtering/spam, or other tasks, or their server may need to be faster to process mail in general.
  • The mailbox may be full
  • Anti-Virus/Spam screening programs
    Mostly, these programs are quick and usually only delay from a few seconds to a minute. However, this process can take longer, as emails are screened in the order they are received, and the overall file size or attachments can cause delays.
  • The send/receive cycle of the email program, ISPs, and or Mailbox Providers
    Many providers have timed interval cycles for sending/receiving. The most common cycles are from a few seconds to 15 minutes.

Please contact our Customer Experience Team if you still need help determining what may be causing a delay. 

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