"My boyfriend is a journalist."
Translation:Mi novio es periodista.
Then there seems to be an error in the program as I answered it with " mi novio es un periodisto " thinking because boyfriend was masculine, journalist should also be masculine. It said I was partially right with a typo and displaying "mi novio es un periodista" as a correct answer.
Yes, except you would normally drop the "un" when making statements about a profession:
Mi novio es periodista