In August of last year, we accepted a proof of flood insurance coverage by mistake. We thought it was proof of renewal, when it was actually an expiration notice. We did not discover the error until March of this year.

During that time, the borrower had a coverage gap from 8/25/25 to 12/12/15.

I believe that we need to have force place insurance coverage for this gap and we have force placed to cover that time period.

What I am unsure about is mailing the force placement letters to the borrower. Should we mail a 45 day letter to the borrower, followed by the 15 day letter, then the force placement letter?

Or should we do something else?

Since you discovered this in March, you should have begun your force placement procedures at that time (upon discovery). You can't cover the gap that already occurred. If you haven't already, Mail them a letter today and start the 45 day clock.