Customer gets an red banner error message

[DesignBeyondLimits]

I've been trying for days to get this resolved. I have a tiny etsy store and everyone can purchase items from every etsy shop except mine. There's a red banner error message that pops up when anyone tries to purchase that says there was an error and unable to put item in your cart 

[NanaLetha]

I get no red banner but I'm not going to buy a shirt without measurements and sizes.

[BagmakerSupply]

@DesignBeyondLimits: "Customer gets an red banner error message" How do you know this?

As an aside, are you aware that you are hurting yourself by having an incomplete shop (no location, about, policies)? And are the photos your property and do you have permission to use the Eagle's intellectual property on your products?