|Quoting G5ive (Reply 7):|
It has to be name index.htm NOT html if this is the first page to the website.
Don't know about the specifics of 1&1, but in general the .htm extension exists only because of the legacy of the DOS/Windows 3-letter extension. The traditional extension for these types of files is .html, as Unix/Linux don't have that limit. Most of the time though, web hosts configure their servers to accept either for a default page.