I noticed when using the fully qualified domain name (FQDN) to access the Fossil website the SQLite Homepage is loaded instead.
To repeat, make sure to include root (.) at the end of the domain name in your web browser's URL field.
Interestingly, sqlite.org. does what is expected.
Fix to althttpd.c is here: https://www.sqlite.org/docsrc/info/13343b49ccb9c515