Navigating the Amazon Pay Integration Maze: A BigCommerce Merchant's Unresolved Challenge

The Amazon Pay Integration Conundrum: A Critical Unresolved Issue for BigCommerce Merchants

Amazon Pay is a pivotal payment gateway for many e-commerce businesses, offering a trusted and convenient checkout experience that can significantly boost conversion rates. However, a recent BigCommerce forum thread highlights a severe and persistent issue preventing merchants from successfully integrating Amazon Pay with their stores. This challenge, first reported in April 2026, involves a specific redirect and authentication prompt that has left one merchant, Silvio Vidal, in a frustrating deadlock between BigCommerce and Amazon Support.

The Core Problem: Redirect to 3p-auth.bigcommerce.com and Basic Authentication Prompt

The setup process for Amazon Pay within the BigCommerce control panel (Settings → Payments → Digital Wallets → Amazon Pay → Set up) initially appears to proceed smoothly. The merchant reaches the crucial 'Share API keys with BigCommerce' step. However, upon clicking this button, instead of completing the connection, the user is redirected to a BigCommerce-controlled authentication URL:

https://3p-auth.bigcommerce.com/omni/amazonMaxo/...

This URL correctly contains Amazon registration and authentication data, including an MWSAuthToken. Yet, the process is interrupted by an unexpected Basic Authentication prompt, demanding a username and password. This prompt prevents the connection from finalizing, leaving Amazon Pay stubbornly unconnected in the BigCommerce control panel.

Extensive Troubleshooting and Support Standoff

Silvio Vidal has undertaken comprehensive troubleshooting steps to resolve this issue, demonstrating a thorough attempt to isolate the problem:

• Testing across multiple browsers: Firefox, Chrome, Opera
• Clearing browser cache and cookies
• Using different devices
• Experimenting with various return URL configurations
• Verifying approved domains within Amazon Pay settings
• Providing detailed HAR files, screenshots, and videos to support teams

Despite these efforts, the issue persists. Both BigCommerce and Amazon Support have investigated the case, but the merchant finds themselves caught in a referral loop. BigCommerce has linked the issue to an internal engineering ticket, EXT-348, suggesting it might be related to missing headers during the callback or credential sharing process in Amazon’s new UI flow. Conversely, Amazon Support has referred the issue back to BigCommerce, asserting that the redirect to 3p-auth.bigcommerce.com and the subsequent Basic Authentication prompt indicate a problem within BigCommerce's callback process.

A Call to the Community: Unanswered Questions

With Amazon Pay being business-critical, the merchant's plea to the community underscores the urgency for a resolution. Key questions posed include:

• Are other merchants experiencing this specific Amazon Pay setup issue?
• Has anyone successfully connected Amazon Pay to BigCommerce recently?
• Are there any known workarounds for the 3p-auth.bigcommerce.com Basic Authentication prompt?
• Is there an alternative method to connect Amazon Pay, perhaps manually or via another provider?
• Has there been any update regarding engineering ticket EXT-348?

As of the time of this insight, the forum thread has received 0 replies, meaning no community-provided solutions, workarounds, or updates have emerged. This leaves the merchant, and potentially others facing the same issue, without a clear path forward. This situation highlights a critical gap in the BigCommerce ecosystem's ability to seamlessly integrate with a major payment provider, impacting merchant operations and customer checkout experiences.