Why is this social security number not in the system?

If you need to inquire, you can only inquire at the social security office of the insured place.

You don't have to worry. In addition to logging in to the local social security network to inquire (sometimes the function is imperfect and unstable), you can also inquire in the following ways:

(1) Local Social Security Bureau

(2) Call the Social Security Bureau service number 12333 (local call fee).

Remember: the inquiry requires my ID card or social security number.

I suggest you apply to the local social security bureau for inquiry, and you can get satisfactory results.