Sorry, how exactly do you sign a specific address somewhere else.
I think he meant signing a different address in a different wallet of course . You can't sign the said address on a different wallet unless you import its private key . And unfortunately to the best of my knowledge, you can't export private keys on coinbase . I've also tried signing a message on my old coinbase account, It seems the problem is on them, I contacted their support already about this matter . I will update you if coinbase replies although I am expecting it will take several days as they have said here:
So If you have a different wallet ofc it'll be a different address . I suggest that you should just sign that one especially if you're in a hurry .
