Was it for the AGI? That's a common reject. Here's some info for that one.
When did you file 2017? If it was late in the year try putting in zero for the AGI. And see this, https://ttlc.intuit.com/replies/5595742 If you can’t get it to efile you will have to print and mail it.
Help with finding out why your return was rejected and also help on fixing it so it can be rfiled has been provided for you below.
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