Do the names (salutation shouldn't matter) match exactly between your OP account, the tickets you are buying and the information you're putting in the TSA SecureFlight crap that CO solicits on their behalf all match exactly? If not then you should fix that first. Things like Mike v Michael can definitely throw the systems off, sadly.

Also give CO your birthdate to put in your OnePass profile and on the SecureFlight data. That often helps.

If none of that resolves the issue then you'll probably have to deal with the TSA's TRIP program. Good luck with that; you'll need it.