You say have a qualifying child, but you don't say what's different about your situation. The automatic payments are for those who claim the child, on a tax return, every year, and get a direct deposit of their refund and there is no one else who could have already claimed that child.
What are the new Child Tax Credit advance payments?
https://ttlc.intuit.com/community/family-tax-credits-and-deductions/help/what-are-the-new-child-tax-...
