If you have multiple databases and db-filter setup, Reset Button emailed link is wrong, it defaults to localhost:7073, but if you only have one database it works
You need to set the -d flag on start to call flectra which is the main database of this instance. And you also have to check the web.base.url in system parameters which is used for all links.
But the best approach is to only have one database per running instance. We always use one instance per database. So on our server whe have about 5 - 10 instances running (production, test, dev environments). For this docker is a very good solution to not use too much disk space.