Itunes rejecting my podcast picture

I'm trying to validate my podcast and getting the following message

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.

I've converted it in Corel Draw, it's in PNG format, 1510x1500px, 72dpi, should be RGB and is being hosted by Podbean, but continuously get a failed validation message

I've linked my feed and included the direct link. I'd appreciate any advice/help

https://feed.podbean.com/fossilfic/feed.xml

https://fossilfic.podbean.com/