Illinois state taxes says there’s a problem with line 21(military pay) I imput the amount I’ve received this year, Illinois doesn’t tax military members so what’s my problem?

[MaryK4]

You may subtract tax-exempt military pay that is in your AGI, including

• pay for duty in the armed forces, including basic training,
• pay for duty as a cadet at the U.S. Military, Air Force, and Coast Guard academies, as a midshipman at the U.S.
  Naval Academy, or in ROTC, and
• pay for duty for serving in the U.S. Armed Forces Reserves or a National Guard unit, including a National Guard unit of another state.

For more information please see Publication 102, Illinois Filing Requirements for Military Personnel.