PayPal Is Unable to Add the Social Security Number to the Database

Identity Verification Process
PayPal requires you to provide your Social Security number -- along with other personal information such as your legal name and bank account number -- so that all users can have smoother and more secure transactions. According to PayPal's Privacy Policy, it collects the data to "compare information for accuracy and verify it with third parties." Once your identity is confirmed, you have more privileges as well as validity as a seller, depending on what type of account you have.
Account Limitations
If PayPal is unable to verify your identity, your account will be limited in some capacity. New accounts initially have a withdrawal limit of $500 per month. Other limitations may be on your account if PayPal encountered some conflicting information about your identity. If you are trying to lift the limits on your account but PayPal isn't accepting your Social Security number, you have an identity problem on your hands. PayPal won't remove your limits until this problem is resolved.
Possible Problems
Conflicting information about your identity can happen for a variety of reasons. If you've ever had a different name, spelled it differently, or have records of slightly different addresses or account numbers, any of these can trigger an error. And of course if you're illegally using a false identity, the system has caught you. For most honest account users, however, minor discrepancies can be resolved once you provide PayPal or its partnering identity verification services more information.
Resolution
If PayPal has automatically noticed the identity verification conflict, it will send you an email asking for more information. In this case, provide the information requested. You should receive a response within three business days. If PayPal doesn't contact you, visit the Resolution Center and click "Steps to Remove Limitation > Resolve." Follow the instructions on-screen. In some cases you may be requested to provide more information or contact one of PayPal's third party business partners to resolve the conflicting information. If you're having trouble or additional questions, click "Contact Us" at the bottom of any page on PayPal's website.