Email FAQ

Why are my open rates dropping?

Totally get why at first glance that would look alarming, but open rates have become pretty unreliable across the industry. A few things are contributing to this:

• Apple Mail Privacy Protection — Since iOS 15, Apple automatically loads images (including tracking pixels) whether or not someone actually opens the email

• Gmail prefetching — Google preloads email content to improve loading speed, which triggers open tracking

• Spam filters — Security systems open and click links before delivery to check for malicious content

We do make an attempt to filter out machine opens on our end, but it's not reliable since mail clients change their processes regularly. This affects everyone — even SendGrid says they can't distinguish between human and bot opens because the signals are identical.

A couple good reads on this:

• SendGrid's take on non-human engagement

• Customer.io's deep dive on bots skewing metrics

Click-through rates, conversions, and reply rates are better indicators if you want to track actual engagement.

What metrics should I focus on instead of open rates?

Since open rates have become unreliable, focus on metrics that indicate real engagement:

• Click-through rates — More reliable since they require actual action

• Conversion rates — Track how many recipients take your desired action (purchases, signups, downloads)

• Reply rates — Especially valuable for B2B campaigns

• Unsubscribe rates — While not positive, these remain reliable and can indicate content relevance

• Revenue attribution — Measure actual revenue generated from your email campaigns

Why do my emails show as opened but no one clicked?

This is often due to email clients pre-fetching content or spam filters checking links. When Gmail prefetches emails or Apple Mail Privacy Protection loads images automatically, it triggers the open tracking pixel without the recipient actually viewing the email. This is why open rates can appear inflated while click rates remain low.

How does Mantle filter out machine opens?

We attempt to filter out machine opens using signals like user agent strings, IP addresses, and timing patterns. However, this filtering isn't perfect because:

• Email clients regularly change their processes

• Spam filters use different methods that are hard to detect

• The signals from bots and humans are often identical

This is why we recommend focusing on click-through rates and conversions rather than open rates for measuring campaign success.

Are my emails actually being delivered?

Yes! If you're seeing opens (even if they're machine opens), your emails are being delivered. The more reliable indicator of delivery is your bounce rate — if that hasn't changed, your emails are reaching inboxes. The drop in open rates is more likely due to email client behavior changes than delivery issues.

Why are my emails going to spam even though my domain is verified?

This is a common issue, especially with new sending domains.

Verifying your domain (SPF, DKIM, and DMARC) is a required first step, but it does not guarantee inbox placement. Once an email leaves Mantle (via SendGrid), whether it lands in the inbox or spam is determined by the recipient’s email provider (Gmail, Outlook, etc.).

Here are the most important things you can do to improve deliverability:

• Warm up your domain — New sending domains need time to build reputation. Start with small batches and gradually increase volume over a few weeks.

• Send to engaged recipients first — Email providers learn from recipient behavior. Sending to users who open or click helps build positive reputation.

• Be careful with email content — Avoid spam trigger words, excessive capitalization or punctuation, and image-heavy emails with very little text.

• Test with real recipients — Sending test emails to yourself often results in spam placement. Testing with real recipients gives more accurate signals.

• Help train Gmail filters — If testing with Gmail, have recipients mark the email as “Not spam” and add the sender to contacts.

• Confirm DMARC is set up — Make sure your DMARC record is configured and showing as verified in Email → Settings → Domains.

Improving deliverability takes time. Consistent sending patterns and positive engagement gradually build sender reputation across inbox providers.