ERROR - External Product ID Type

Hi Guys,

Hoping you can help me I am trying to update my listing but I keep getting the below error shown in the image.

Nothing has changed in terms of EAN / UPC / ASIN. I cannot fathom how this error is coming up, and as usual SS is being unhelpful.

Can anyone point me in the right direction, or another thread with the same issue?

Capture.JPG 821×251 35.1 KB

Thanks a bunch!!