Who is the mortgage with? If a new mortgage company, then get the insurer to reissue the check in the name of you and the new mortgage company and see if that will work. If not, get the insurer to reissue just in your name since the old mortgage company is not involved.
Why did it take the insurer 5 years to issue a check and why isn't the new mortgage lender named as a loss payee? Have you changed insurers?