Why can't I sell on Coinbase?

I'm curious, why exactly are you unable to sell your cryptocurrency on Coinbase? Have you encountered any specific error messages or issues when attempting to make a sale? Is there a certain cryptocurrency that you're trying to sell that's not currently supported by Coinbase? Or perhaps you're facing some verification or account-related challenges that are preventing you from completing the sale. I'd love to hear more about the specifics so I can better understand the situation and provide potential solutions.