I have been listening to Maher Zain (A Islamic music creator) since 2014. Through his whole career he made only Islamic music. His songs encourages people to follow the Islamic path. His all lyrics are praising to Allah & prophet Muhammad. So is it haram to listen Maher Zain's songs ?
If any song includes music, it will be haram. However, if it includes duff only, it will be mubah. And the music must not contain any haram ideas, meanings, and leading.
For a more detailed answer, read an article in Islamqa about it-