Does R2 support Presigned Post Policy?

Hi,
I can upload files using presigned Put urls.
But I can’t limit the file sizes for the upload.

As far as I know I can limit this using post policy.
I created post policy using createPresignedPost function from S3 JS SDK.

But when I try to send a post request to the url I receive an error
You are not authorized to view this bucket

How can I limit the file size if post policy not supported yet?

Thank you