I have only been involved in creating and renewing certificates for different domains for a month, so I would definitely say with very little experience in this regard.
The situation I would like to understand is this: there is a classic nginx that is operational and works well as a reverse proxy for different domains, redirected to internal machines and with certificates already created and valid with the various .confs. However, I have to replace this "classic nginx" with nginx proxy manager (I'm working with docker containers) and therefore I was trying to create certificates from the npm dashboard, hence the doubts. With new domains it creates the certificate, but if I try to create a certificate for domains that already have a valid certificate, it fails.
So is this the problem? Is it not possible to create certificates for domains with an already valid certificate but is it only possible to renew them? I ask for confirmation because I would not like to find myself with problems in the migration phase or a subsequent malfunction.
Thanks and have a good day everyone