CORS error, Reactjs

I’m developing a simple CMS that would access my beacons so I can edit or delete some attachments. I’m using currently using Reactjs. I made a simple fetch request to try and access the data, but I get this warning. And I don’t receive my data. I do not know what seems to be the problem.

"Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://cloud.estimote.com/v3/attachments. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing)."
"Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://cloud.estimote.com/v3/attachments. (Reason: CORS request did not succeed)."

Web browsers implement a security mechanism, which by default prevents a website aaa.com from making requests to anything outside aaa.com. So if you have my-cms.com, you can’t make direct network requests to cloud.estimote.com.

You’ll instead need to make requests to cloud.estimote.com from your backend, and not from your frontend React app.

I understand. Thank you