Since you've successfully scanned your switch than you've already enabled SNMP on the switch, no other ports or protocols should need to be enabled. Usually these issues are resolved by rescanning both the asset and switch.
If the issue does persists, then the easiest way to resolve it is contact our support team and give them some screenshots of the problem so they can forward you troubleshooting steps and maybe some debug options/tools.
When a switch is scanned by Lansweeper, it will also scan the MAC addresses connected to the ports on the switch. Once scanned the MAC addresses are compared to existing MAC addresses in the database to link assets to the port they are connected to. If no match is found, only the MAC address is displayed.