Recovering from an old Wallet
As a workaround for the problem that you are facing - instead of using Bitcoin Core to send BTC to your account with the exchange, you might want to try exporting your wallet's private key from Bitcoin Core, then importing the private key to your account at the exchange.  See https://wallet.coinbase.com/faq/ (under 'Can I switch from my existing wallet app like Metamask, MyEtherWallet, etc.?') for information on how this is done with Coinbase.  Then, your BTC will be available in your account at the exchange.