My daughter, who is a dependent, efiled a return last year and it got rejected. However, she did not notice the rejection.The IRS is not accepting the 2018 return as well

Since 2017 was rejected then enter 0 zero for the AGI to efile 2018.  

Why did 2017 reject?  Probably doesn't matter.  She has to print and mail it now.  Or if she has to fix something see How to finish a prior year online return   https://ttlc.intuit.com/replies/4186197