Magento 2.4.0 known issue: blank product pages when Klarna On-Site Messaging design field is left blank

This article describes a known Magento 2.4.0 issue with Klarna payment method, where enabling Klarna on-site messaging without specifying a design theme, results in not displaying product pages on the storefront correctly (product pages appear blank).

Affected products and versions

• Magento Commerce 2.4.0
• Magento Commerce Cloud 2.4.0

Issue

Prerequisites: Klarna payment method is enabled.

Steps to reproduce:

1. In the Magento Admin, go to Stores > Configuration > Sales > Payment Methods > Klarna > Klarna On-Site Messaging.
2. Set Enable to Yes.
3. Leave the Design theme field blank.
4. Save configuration by clicking Save Config.
5. Go to storefront and navigate to any product page.

Expected result:

The page loads successfully with default design theme applied for Klarna on-site messaging.

Actual result:

A blank page is displayed.

Solution

If enabling the Klarna on-site messaging, always ensure that the Design theme field is not blank.