I purchased Linux hosting from 1and1.com. I added a domain registered elsewhere as an external domain to my 1and1.com account. I changed the DNS settings. I set up a home page for my site. When I browse to the site I get redirected to example.com/defaultsite (where example.com is my domain). When I browse to the home page explicitly I see my page flash and then it redirects to defaultsite.
I called 1and1 support and he made some changes to my home page. One thing he did is to remove the following:
<meta http-equiv="Refresh" content="0;url=defaultsite" />
Without that I get my home page as the default page and everything works. When I add that back in, the problem happens again. I remove it again and the site works.
In 1and1 ionos FTP root folder, by default there's an index.html file which is causing the trouble and contains the troublesome "defaultsite" code snippet. If you install wordpress in the root directory, this file is served INSTEAD of the necessary wordpress index.php file. So, the solution is to rename the troublesome file to BACKUP_index.html (or delete it) and the gears will start turning again. Viola!