Port mapping information is pulled from SNMP. If the switch is successfully scanned through SNMP, but port mapping information hasn't, SNMP on the switch isn't providing the port mapping information. There is not much we can do about this, unfortunately. A firmware update of the switch may resolve the issue.
You can confirm that SNMP isn't providing the information by performing a connection test to the switch with
this tool. If the Connected Devices list at the end of the test is empty, SNMP isn't providing the information.