My website has been created using Flutter and is hosted in a subdomain (e.g. web.domain.co.uk/#/page) and on my frontend I am calling the track endpoint to send data to Mixpanel, unfortunately I get a CORS error like the following:
Access to fetch at 'https://api.mixpanel.com/track/?data=[...]' from origin 'https://web.domain.co.uk' has been blocked by CORS policy: Request header field access-control-allow-origin is not allowed by Access-Control-Allow-Headers in preflight response.
I checked the following support pages
But none helped, how can I fix this problem?