Is the mortgage interest limited in some way? I had $3900 in mortgage interest, but in the summary, it allowed only $350 or so?

You may not have checked the box where it asks if the mortgage is secured by the property. Edit the 1098 Mortgage statement. You'll get to the Is this loan secured by a property of yours? screen. See my screenshot below.

Here are the new tax law requirements and limitations regarding the mortgage interest deduction: https://ttlc.intuit.com/replies/3300473 

[Edited 4-14-19|11:47 am PST]

I thought this was the answer, but I could not find where the box to say the mortgage is secured by the property.  Going through the series of screens, it doesn't come up.

 Edit the 1098 Mortgage statement. You'll get to the Is this loan secured by a property of yours? screen. See my screenshot in my answer above.