Hey @nicolas.spehler, Sorry about that, I misread your last response.
We just took a closer look at your page, and a colleague could find the 403 error.
Because your site is built with Gatsby and it's statically generated, it shouldn’t be making any requests to the API. This makes us think it’s something to do with the toolbar, which makes queries to the API to use them in the preview mode. Therefore it’s the only thing that could be making requests.
Could you tell me if the people who are seeing this same issue are Prismic users, i.e., people on your team?
Maybe it’s someone with another prismic expired cookie visiting the site that isn’t valid, or maybe the person logged out, and it was still cached. I don’t think non-prismic users are seeing this issue, I think it’s maybe a preview cookie conflict in your Gatsby app.
Let me know