Hi all, I thiink I may have found a sollution to generate a certificate.
Instead of renew, go to the Add SSL certificate option, Let's encrypt and select use a DNS challange.
Enter your DNS provider, in my case Duckdns and the token that you have when you log in to duckdns page.
It generated a new cert. Make sure you backup your existing one by downloading it, delete the old cert and config the redirect by selecting the new cert. An easy way to tell which one is the new one is by looking at ethe expiry date.
Hope it helps.