NFT Marketplace - Buy listing error: cannot estimate gas

This error response comes from the chain. Tatum proxies the error message in the response.

Tatum does not have an endpoint to estimate gas for the buy operation (as of the writing of this article), since there is no easy and reliable way how to do it. 

Workaround and additional info from Ether docs:

The buy endpoint at Tatum can accept fee object where you can set your custom "gasPrice" and "gasLimit". You can give it a try to avoid automatic fee estimation done by the chain.

To dial in an appropriate gas limit, try a value that is much higher than you expect, and then make a few transactions to discover reasonable values, and then you can reduce this value down to that ballpark.

Additional information available at the following link.