Error! The value specified is invalid.

Hi, I can't add any new products. As soon as I complete all the required information, the button "Submit" refreshes, and "Error! The value specified is invalid " appears on the screen without specifying what box needs to be adjusted or where the issue is.

I checked all the boxes, and none of them is red, suggesting an issue with the data entered. All looks ok, but I can't submit the product.

How can I solve this?