Box17 on the W-2 is the amount of state tax that the employer has withheld and sent to the state - the amount of state tax that you have paid during the year.  FLI may stand for Family Leave Insurance.  You may want to contact your employer for an explanation.

Since you have an amount of withholding in box 17, I suggest you contact your employer and inquire as to where your FLI tax is or what it is for.  You may need a corrected W-2 or your the state tax withheld returned to you.

[Edited 03/15/20]