Your character possesses some form of magical disability, whether it be a lack of magic, difficulty casting spells, or anything similar.

This can extend to innate magic, proficiencies, or even both. Those lacking their innate magic may lack abilities that most of their kind typically possess. (Your character could lack or struggle with 1 or 2 abilities that their species typically has, more, or even all of them at once. For example, a ringling that can fly, but cannot heal others.)

You can read about the various species' magical disabilities, how they impact them, how they accommodate for them, and more-- on their respective species pages.

For species with traits that tie into their magic, this trait bypasses them. For example, a standard sqwagul typically has average magic, however your sqwagul could be unable to cast spells despite this.