[▲ Vercel Community](/) · [Categories](/categories) · [Latest](/latest) · [Top](/top) · [Live](/live)

[Help](/c/help/9)

# (Vercel error today) TypeError: Failed to execute 'fetch' on 'window': …with a request object that has already been used

167 views · 2 likes · 2 posts


Arsenalist (@arsenalist) · 2024-08-20

I'm getting this error when using React Toolkit on POST requests. No changes were made to my application and all was working. Some change was made by Vercel today regarding fetch() or something related that is causing this. 

Can be reproduced by trying a POST request with react toolkit.


Tom Lienard (@quiibz) · 2024-08-20 · ♥ 2

Hi! I'll link the GitHub issue that you opened at Posthog just to track it here too, in case other folks have the same issue: https://github.com/PostHog/posthog/issues/24471

The [fix](https://github.com/PostHog/posthog-js/pull/1371) was apparently released in `posthog-js@1.157.1` ([GitHub comment](https://github.com/PostHog/posthog/issues/24471#issuecomment-2298280850)).