I need to insert a few lines of HTML code into the seattle.master file, but I don't actually want to edit the seattle.master file. So I copied the same file, inserted the code and set the copied file as the default master page.
After that everything went well for me as an owner, but the visitor can't access the website. I compared the permissions between these two files and everything is the same, but the visitors still can't access the site. What could be the problem?