Someone learning Spanish as a second language will have to remember that it's máquina and not máquino when speaking or writing it, though (and will then probably be quite confused if they ever meet some guy nicknamed El Máquina, which would somehow be a perfectly cromulent nickname in Spanish).
Confusing genders when speaking or writing is one of the most common mistakes amongst people new to the language, because while everything else has some form of rule, this doesn't (sure, when reading or listening you can most of the time use the word ending, and you'll probably have an article, too, but when you are the one speaking or writing you have no option but to just know a word's gender, or how it ends, which is the same thing).