If you used this form 8815 in TT for years before 2018, TT may be pulling the form into your 2018 return by default. Can you delete the form from your return or clear it using question answers on the step-by-step entries?
In case anyone lands here. I was able to find a solution by deleting this form (as it was not relevant for the current tax year but was presumbably pulled over from previous tax year, where it was relevant) via the Tax Tools delete a form option and described here: https://ttlc.intuit.com/community/taxes/discussion/re-why-is-turbo-tax-telling-me-form-8815-us-address-should-be-blank/01/1300311/highlight/true#M470153
Why does TT insist on including this form, when I am not taking this credit? How can I make TT quit the error loop?
See How to Delete to eliminate the form.
If the program thinks it is needed, it will stay. You will have to dig into the program and find the root.