There Is No (S, G) Entry in the SA Cache

No (S, G) entries are sent to an MSDP peer through Source-Active (SA) messages.

The import-source command filters the (S, G) entries sent from a local domain to the remote MSDP peer through SA messages. If acl is not specified in the command, the switch filters out all the (S, G) entries.
If the import-source command is not configured, the switch sends all (S, G) entries in the local domain to the remote peer. When MSDP fails to send (S, G) entries in the local domain through SA messages, check whether the import-source command has been configured correctly.

Check whether the two MSDP peers have learned ARP entries from each other.
Run the display arp all command to check ARP entries on the two devices.
Check whether the two devices have reachable unicast routes to each other.
Run the display ip routing-table command to check routing tables of the two MSDP peers.
Check whether the interface addresses used to set up MSDP peer relationships are correct.
Run the display current-configuration command to check whether the local interface address is the same as the remote MSDP peer address configured on the remote device.
Check whether any SA message filtering rules are configured.
Run the display this command in the MSDP view to check whether import-source is configured with a specified ACL that filters (S, G) information.