discrepancies between K-1 line 2 and 8825 line 21

I received a K-1 which has line 2 amount  (Net Rental Real Estate Income(loss)) which is different from 8825 line 21 amount (big difference). Could you help if there is a way to input the different amounts or I need to go back to my K-1 issuer to get it corrected? Thank you!