My tax return for 2018 was rejected and I missed that. Is it too late to refile them this year?

No, it is not too late, but you cannot e-file it.  E-filing is closed for 2018 returns.

 

If you have any changes/corrections at all to make to your 2018 return, you now have to complete it using desktop software, which you must download to a full PC or Mac  (not to a mobile device).

https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turbotax-online

If you already paid for your online software you can ask customer support for a download of the desktop software.

They are available from 5 a.m. to 5 p.m. Pacific time Monday-Friday.

https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number

 

 

 

If you are getting a refund, there is no penalty for filing late.  If you owe tax due, then file and pay the amount due as shown on the Form 1040, but expect a bill later from the IRS for the penalty and interest you will owe.  Only the IRS will calculate this—TurboTax will not calculate it.

No, not at all. How do you know it was rejected? Turbo told you--in which case resubmit, although likely have to mail it. If IRS sent letter respond to the letter