So if you do the Docker setup, obeying the instructions and substituting everything that needs to get substituted, but don't proofread the files in detail and so miss that line 40 of docker-compose.yml doesn't have the variable {{domain}} like in every other location you need to write your domain, but instead just says LEMMY_UI_LEMMY_EXTERNAL_HOST=lemmy.ml and so you fail to change it away from lemmy.ml... then, everything will work, until you type in your admin password for the first time, at which point your browser will send a request to lemmy.ml which includes your admin username, your email address, and the admin password you're trying to set. And, also, of course your IP address wherever you are sitting and setting up the server.