I agree with Joseph's statements, the first step if you haven't already done so is to contact your title company and have them check their register to confirm the check wasn't deposited. Depending on which bank/system they use, they should receive regular updates on positive funds in the account so they can follow up on uncashed checks. Unfortunately, once a check is cut from their ledger and mailed, it can be very difficult to follow up on undeposited checks, as the assumption is the check made it to its correct destination and is now in the hands of the other person or company to apply the funds correctly. If you figure each file closed mails out 6-10 checks a piece, to agents, brokers, municipal services, etc, depending on the title companies volume, they might be mailing out 100s if not thousands of checks a week, and if the check isn't returned to their office, the file is marked as closed and unless someone reaches out, no one is going back into the register.
If the insurance agency confirmed they received the check but they didn't cash it, then that's a whole separate issue that you would need to speak with them directly, or your agent who helped fill out the insurance request to find out what went wrong.