Troubleshooting product block display and loading issues in email clients

Last updated: May 13, 2026

Product blocks may sometimes fail to display correctly or load properly in email clients like Gmail, especially on mobile devices. This article covers the most common causes and solutions for these issues.

General guidelines

If your template is not functioning correctly or products are not loading promptly, try deleting the product block and setting it up again. Occasionally, blocks may experience minor glitches, and recreating the block often resolves these issues.

Email size optimization

The most common cause of product block issues is exceeding the 200 KB email size limit. This limit is measured after all conditional logic is processed, meaning the final rendered email must be under 200 KB.

Optimize conditional content

When using multiple product grids with conditional logic:

  • Use text blocks with display logic inside Zaymo's builder

Product group size limitations

Large product groups (50+ items) can cause system overload and prevent product blocks from rendering entirely. If product blocks aren't appearing despite correct settings:

  1. Check if any product groups contain an excessive number of items

  2. Reduce the size of large product groups

  3. Delete unused product groups with many items

Product grid troubleshooting

Update outdated product blocks

Validation errors may be caused by using an older version of the product block. To fix this:

  1. Delete the existing product block

  2. Drag in a new product block from the block library

Newer versions have larger limits and improved functionality that resolve validation issues.

Hide navigation buttons

To hide navigation arrows above product images in grid blocks:

  1. Click on the product image

  2. Navigate to the 'Content' panel on the right

  3. Toggle off the 'Navigation Buttons' option

Managing rate limits

Large email campaigns can hit rate limits, causing 404 errors or interactive content to not load. To prevent this:

  • Add more API keys

  • Utilize Klaviyo's gradual send feature

Zaymo provides notifications about rate limits through in-app alerts, Slack messages, and email.

Intermittent rendering issues

Product grids may experience intermittent rendering issues in Gmail and other email clients, showing fallback sections or failing to load images properly. These issues can be intermittent and may not affect actual customer emails.

If you experience persistent rendering problems, try duplicating your template, as this can sometimes resolve display issues.

Template update workflow

Remember that templates do not auto-update from Zaymo to your email platform. After making changes in Zaymo:

  1. Re-export the template from Zaymo

  2. Insert the updated template into your email flow

You don't need to clone templates to re-export them - you can export the same template with your updates.