Sometimes an SMA Contract is not visible in CRM.
If it's for a brand new machine, sometimes the SMA contract was never created in Customer Care.
If it's not a new machine, first check the IBase under the first level in the ERP Active Contract assignment block.
Also click on the second level and see if visible under ERP Contract assignment block.

If not, there could be an error in the SMA contact where the product ID is missing, or there's a typo on the serial number preventing the link between SAP ERP and SAP CRM.

Go to SAP ERP.
Go to VA43 Display Contract.
Enter SMA Contract Number.
Double-click on a line item listed under the serial number.
Scroll Right to Additional data B to see product ID & Serial Number next to IBASE.

If either the product id or the serial number are missing, or if there's a typo on the serial number, that breaks the link between SAP ERP and SAP CRM.  Send an email to the Software Team Lead in Customer Care (Jody Tenboer) and she will get it fixed for you.