I have requested a transfer for my traditional IRA and received a check made payable to myself. The check will not be deposit until January. How do I report as a transfer

IRA transfer - I have requested a transfer for my traditional IRA and received a check made payable to myself only. I am mailing the check to another financial institution but it won't make there until January 2018. The issuing institution coded as a premature distribution, but the check will be deposited within the 60 days allowed by law into another IRA but on two different years. How can I explain to the IRS that this was a transfer and not a premature distribution?