Every time gives same -511% accuracy

#1

tried submitting with different models, gives same -511 score on submission while acc. to my model, accuracy score is 87%.

#2

hi sanchit;
1.how are u testing accuracy of ur model ( by validation split) 87??
2.if u are getting -500% in all the models this can be due to faulty generation of sample submission file .
3.or case can be u are normalising data and predictions and not denorm them back