Invalid SSN/Activation Code

We have a borrower/investor trying to register on our Online-CEF site. When they enter the activate code and try to register, they are getting an error "Invalid SSN/Activation Code". We have verified the activation code and even selected a new one, but the error continues

When this error is received, double-check the social security/tax identification number within the DDI-Connect system on the constituent's record. It is possible that the SSN/TIN was typed incorrectly when the record was entered.

If the SSN/TIN is correct within the constituent record and you have verified the activation code yet the error persists, please contact DDI Client Support for additional assistance.