How to fix a 417 error in Predictive Search?

Topic summary

A user encountered an “Uncaught (in promise) Error: 417” when implementing Predictive Search in their Shopify theme.

Root Cause:
The 417 error (“Expectation Failed”) occurs when the Shopify Predictive Search API is used with an unsupported language.

Solution:
Change the store’s language setting to “English (Default)” in the Shopify admin. The Predictive Search API only works with specific supported languages, and using an unsupported language triggers this error.

Status: Resolved - the original poster found the answer in Shopify’s API documentation and confirmed the fix.

Summarized with AI on October 31. AI used: claude-sonnet-4-5-20250929.

Uncaught (in promise) Error: 417

anyone know how to fix it?? Please

I found the answer !!!#### Expectation failedAnchor link to section titled “Expectation failed”

If your theme isn’t using one of the supported languages, then the API returns the following error:

Change your language to English (Default)