I have 2 sons with my ex-wife. We have been divorced for several years and file separately. Our agreement is such that each one of use claims one child. However, for the COVID stimulus she already claimed both sons. She says she has not submitted her 2019 taxes. When I try to file my 2019 taxes claiming the son I normally claim, the forms are rejected saying someone has already claimed a dependent with the same SSN. Since she has claimed both sons for the stimulus, could this be the reason my taxes are being rejected? How do I fix this?
