Per the IRS Instructions for Schedule A (Form 1040), page 1:
Expired deduction for mortgage insurance premiums.
At the time these instructions went to print, the deduction for mortgage insurance premiums had expired. You can't claim a deduction for amounts paid or accrued after 2017. To find out if legislation extended the deduction so you can claim it on your 2018 return, go to IRS.gov/ScheduleA.