[Observium] observium not showing mac addressses Cisco Switch WS-C3750X-48P-S

Problem:

I have a Cisco Switch that is not showing the MAC addresses in Observium. I have configured SNMP as according to the IPV4 instructions on the main observium website. My other Cisco devices are showing MAC address information fine. I can do a show mac address-table and everything appears when SSH into the switch. Can someone please advise what I am missing or how to get observium to start showing the MAC addresses of this device?

Model number : WS-C3750X-48P-S

* 1 54 WS-C3750X-48P 12.2(55)SE C3750E-UNIVERSALK9-M

Thanks