SKU error message while listing

I’m an Indian seller just getting started. While listing my product, I left the SKU blank since I don’t have the SKU id. Once I finished listing, I could see the auto-generated SKU ID in my draft. However, I could see this error message “There is no record of the SKU corresponding to this update on your account. This commonly occurs when there are other issues on your SKU.”

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how do I solve this? my product doesn’t have product number, upc codes too