CMN.ATO.IITR.000604 - Private health insurance details must match where claiming both your and your spouse's share of rebate

If you're receiving this validation error, make sure you're including the taxpayer's private health insurance policy details. Refer to step 1 on "How to claim for your spouse" on the Australian Taxation Office's (ATO) website#Claimingtherebateforyourspouse.