javascript - Cross Origin error with window.fetch() on Safari -

i'm trying use window.fetch api , along polyfill unsupporting browsers.

my code works in both chrome , firefox, failing in safari (all on mac osx).

function signup(fullname, email, restaurant, source) {   return new promise((resolve, reject) => {     const params = `cm-name=${encodeuricomponent(fullname)}&cm-ottdth-ottdth=${encodeuricomponent(email)}&cm-f-hykuuh=${encodeuricomponent(restaurant)}&cm-f-hyurjd=${encodeuricomponent(source)}`;     fetch(`http://tastyplc.createsend.com/t/d/s/ottdth/?${params}`, {       method: 'get',       mode: 'no-cors'     })     .then(response => response.text())     .then(data => resolve(data))     .catch(error => reject(error(error)));   }); } 

i following error in safari:

xmlhttprequest cannot load http://tastyplc.createsend.com/t/d/s/ottdth/?cm-name=example&cm-ottdth-ottdth=example%40example.com&cm-f-hykuuh=charlotte%20street&cm-f-hyurjd=website%20sign%20up. origin http://localhost:3000 not allowed access-control-allow-origin.

could related polyfill being used - since mentions xmlhttprequest (which i'm assuming polyfill falls-back to).

https://github.com/github/fetch

anything i'm doing wrong or missing? it's driving me nuts.

thanks!