I have no Aliases/Keywords/Groups configured
FARR comes with a ton of them, all enabled by default. They are on the Aliases/Keywords tab. And email is one of them (see the Core_Aliases\Core-Internet.alias" selection). You can disable that alias file if you select it and then uncheck it at top right.
As for the option to only match aliases when you use a specific string, see the option on the Search Behavior tab labeled "Required Alias Prefix".
Another way to solve your problem would be to uncheck the options on the Search Behavior tab that say "Stop search on exact alias match or regex alias match" -- then the alias would trigger but it would still keep searching for matching file results. That would be a bit confusing though, so my suggestion would be to go for one of the other fixes first.