Supplier &1 is blocked

What causes this issue?

Supplier & is blocked; see long text

System Response

You want to create or change data for a supplier. The data related to
this supplier may include personal data and is blocked.

How to fix this error?

The system does not display any data related to the supplier to protect
personal data. You cannot create or change data for this supplier.

Procedure for System Administrators

If you are sure that you want to create or change data for this
supplier, use transaction BUP_REQ_UNBLK to request unblocking.

Error message extract from SAP system. Copyright SAP SE.