Podcast artwork must be between 1400 x 1400 and 3000 x 3000 pixels, JPG or PNG, in RGB color space, and hosted on a server that allows HTTP head requests. But I meet these requirements

Just incase someone on here can help,

Error Messge

 Podcast artwork must be between 1400 x 1400 and 3000 x 3000 pixels, JPG or PNG, in RGB color space, and hosted on a server that allows HTTP head requests.

Current image size Image size is 1600 x 1405 and 242kb but still won't upload JPG

Any help would be appreciated.