Specify multiple categories for custom post template – FATAL ERROR

You don’t need multiple functions. Use an array with in_category to pass multiple slugs:

if( in_category( array( 'ms-conversations', 'artist-of-the-month' ) ) ){
    // do something
}

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)