Jira expression REST API 403 with customer user

We have a super weird behavior calling the Jira expression REST API with a customer user (from customer portal). We always get a 403 error, though the /eval endpoint is also accessible anonymously. This does not seem correct? Any ideas what this is causing?

Thanks
Tobias

Hi @tobias.viehweger,

Could you please share the API call that you made?

Thanks.