Hello, @mdz
Can I please confirm if you have attempted to upgrade again recently and did you run into the same problem?
We had a user reporting the same issue in which the root cause of the problem was actually related to the LetsEncrypt certbot. By default, it is not scheduled to renew SSL automatically unless you setup a cronjob to perform it as mentioned by one of the users here.
Please let me know how it goes on your end. Thanks,