FAQ

Running into issues with your email integration? This FAQ covers the most common problems and their solutions, from blocked images to caching issues.

Blocked product images #

As you probably know, email clients do not support the typical HTML/CSS/JS that run smoothly on all browsers.

For this reason, we use a workaround to produce our Email product recommendations dynamically.

We use a web template engine called Jinja and, through this, we can dynamically print all the product attributes and styles as plain images with links.

These pictures will be displayed in your newsletters as product recommendations.

So, when you open one of our Email contents, our system calls all the product data from our database except one: product pictures.

Those are taken live from your website.

If your server or hosting service comes with a strong firewall, our system may be blocked when fetching the product pictures and so produce product recommendations without the product pictures.

In order to avoid this issue, you need to do this in your firewall settings:

1. Whitelist our IP, which is available here.

2. Whitelist our user-agent, which is called clerk-XYZ.

3. Whitelist our Jinja user-agent, which is called webkit2png or wkhtmltoimage.

These three firewall settings should let our system fetch and render your Email recommendations correctly.

Images not updating #

If updated product images are not showing in your email previews or test sends, it is almost always a cache issue.

Multiple layers can cache images:

• Clerk’s internal cache that speeds up loading of Email Embeds. This is usually not the problem when previewing, as images are only cached when an actual email address is part of the embed code.

• Your email platform’s cache (e.g. Brevo), which frequently causes stale images in previews or test emails.

• The receiver’s email client cache, which typically affects previewing previously received emails.

These fixes usually work immediately:

1. Create a new Email Embed and use that embed code in your email template. Because it is new, none of the cache layers will have cached the images yet. You can create a new embed by following the guide here: /integrations/any-email/email-recs/.

2. Make a non-visual change to your Design (for example, add an extra CSS class without styling) and re-save. This changes the markup and often forces the email platform to fetch fresh images.

Note: When previewing without a real email address in the embed code, Clerk generally does not cache images. Most stale-image issues originate from the email platform or the recipient’s email client caching.