It looks like after an LE cert for one of my Virtualmin servers was updated, the cert for Virtualmin access on port 10000 was changed. I was accessing it using one domain that had an LE cert (can't remember how I copied it there, but it was through the menus). Then, seemingly randomly (I think it was correlated to an automatic LE update), when I logged in I got the HTTPS error that it was the wrong domain name. Looking at the cert, it seems it now belongs to the domain that was automatically LE updated.
How do I change it back? Where is the Virtualmin cert (for port 10000) stored?