See solution here: https://proconnect.intuit.com/community/proseries-tax-discussions/discussion/re-esignature-is-saying...

Short answer: If Tools -> Options -> Electronic Filing ->  Only Transmit Returns when Status is Set to "Return Ready to EF", then that logic is applied as well to whether or not an eSignature can be obtained on a return.   

Honestly, I didn't even know about that setting. I'm not sure it makes sense to me why we're enforcing that flag for eSignature on the request.  If it's there to prevent folks from accidentally eFiling... seems like you wouldn't want to accidentally eFile while you're waiting for the signature. I'm looking into it.