How Email Throttling Impacts Deliverability and Customer Trust

You have designed the perfect email campaign with a sharp copy, your email list is clean, and you hit send, expecting high engagement.

However, some emails get delayed, while others just bounce back. You waited for the response, but all you got was “You have reached the limit of your daily sending quota.”

What happened? You hit email throttling. ISPs intentionally slow down email delivery when too many emails are passed through the server.

The reason? To prevent spamming users with a large volume of emails, especially from senders not yet completely trusted.

This means that email throttling affects your deliverability and customer trust. What are the impacts? Why does it happen, and how can you avoid this?

Let’s find that out.

Why Email Throttling Happens?

ISPs trigger throttling when you send bulk emails too fast. This happens especially when you send emails to a large number of recipients who haven’t engaged with your emails before.

Let’s find out why it happens:

• With a large number of incoming emails, the system can crash. So, to prevent server overload, ISPs implement email throttling.
• A sudden spike in the number of emails is considered a red flag. If the behaviour of your email domain appears even slightly suspicious, the delivery will be slowed down to check.
• ISPs want to ensure a seamless experience for their users. So, if they think that your emails are not wanted, they will delay the delivery to assess.
• Nearly 49% of people receive spam through email. So, if your bounce rates and spam complaints are high and engagement is low, ISPs slow down the delivery.
• When you send a large number of emails from a new IP, ISPs initiate throttling.
• If authentication protocols are missing from your email, ISPs may question your legitimacy, which can slow down delivery.
• There are no more open ports for additional email traffic.
• The inbox of the recipient is full.

How Does Email Throttling Affect Deliverability and Customer Trust?

A high volume of email throttling messages can negatively impact your sender reputation and lead to email deliverability issues.

Here’s a breakdown of the impacts of email throttling:

No Delivery Or Delays

Delays in delivery or blocked email messages pause your planned email campaigns. This especially impacts the user experience when you are launching time-sensitive campaigns. Your customers’ frustration leads to decreased engagement. Moreover, failing to reach your entire audience results in reduced lead generation and conversions.

Reduction In Engagement

59% of customers say that marketing emails affect their purchase decision. What if the emails do not reach them on time or at all? Suppose you planned a campaign to send emails to your subscribers every Tuesday, but the emails don’t reach them on time. What will happen? Your subscribers will gradually lose interest and trust, potentially leading to unsubscribes.

Reduced Testing And Optimisation Strategies

When your emails are delayed or not sent, it becomes difficult to A/B test different elements. This leads to poor optimisation and affects campaign success.

Inconsistency In Performance

You get unpredictable results from campaigns. This leads to fluctuations in open rates, click-through rates, and other metrics. So, you cannot accurately track campaign success.

Poor Sender Reputation

Consistent throttling messages can reduce your sender reputation and increase the likelihood of your emails ending up in the spam folder. When emails land in the spam folder, customers also lose trust in your business.

How To Know Your Emails Are Being Throttled?

Email throttling doesn’t have a clear warning, but by observing certain signs, you can check this:

• Campaign lags
• Delays in opening emails
• Lower clicks than expected
• Delivery is unusually delayed
• “Deferred”, “rate limited”, “or “temporarily rejected” responses or “4xx SMTP Errors” in your logs or reports
• Spike in soft bounces, such as “try again” messages or “452 too many recipients” responses
• Your campaign emails do not reach the inbox all at once

How To Prevent Email Throttling?

To prevent future email throttling events, it is essential to stay ahead and take preventive measures.

Here’s what to do:

• If you have a new IP, start with small batches. Increase the volume gradually over time to build your sender reputation.
• Remove inactive, non-existing, and unsubscribed addresses from your email list to keep it clean.
• Pick a reputable email hosting provider.
• Separate your marketing and transactional email traffic.
• Spread your emails over time with automation to avoid sudden spikes.
• Check the sending limits of your ESP and schedule emails accordingly.
• Monitor your campaign metrics closely for signs of email throttling.

Maintain High Email Deliverability With Crazy Domains

Email throttling impacts your email deliverability rates and customer experience. When your emails fail to land on time or not at all, customer engagement drops. Slow or blocked email delivery can negatively impact your sender reputation.

To check for signs of email throttling, keep a track of your email metrics and logs. And take the right steps on time to prevent future occurrences. Choose a reliable email hosting provider to maintain security, responsiveness, and email delivery.

Crazy Domains offers all this, along with dedicated staff to support, so you always stay connected with your customers.

Sign up for email hosting by Crazy Domains now to ensure the success of your email campaigns.