Unable to submit podcast to apple due to image sizing

Hello,

We have been attempting to submit our podcast through Podbean for a couple of days now ans are being flagged for “Podcast cover art must be at least 1400 X 1400 pixel JPG or PNG, in RGB color space, and hosted on a server that allows HTTP head requests”.

We have used the advice here on the discussions page to refit the image but it appears that the link we are submitting to Apple is resizing the image without our doing. Does anyone know how to fix this?

Link: https://feed.podbean.com/postnutclarityads/feed.xml