I don’t follow completely what you did.
Have you already successfully got a certificate ? (it would appear that way from your comment that certbot said " Congratulations! Your certificate and…"
If so, you need to copy that certificate into your VestaCP.
You then say you tried “certbot-auto certonly --renew-by-default -a manual” Why ? I must be missing something as running this doesn’t make sense to me from your earlier comments.
What is your domain ?