Cisco 3750 interface showing 0% utilization

Honestly I am not sure what the issue is here but you can definitely check what SNMP OID is SolarWinds using to poll this information, through Poller checker tool. In certain cases it could be using an alternative SNMP OID which you can change through this tool.

https://support.solarwinds.com/SuccessCenter/s/article/Use-the-Poller-Checker-tool?language=en_US

Another thing that I could think off is selection 64 bit counter - please check if 'Allow 64 bit counters is allowed under SNMP Port' deselect this option and check if this fixes your issue. By default I am assuming this would be selected, try deselecting this option save it and then poll the device and then check.

How do you do this is simple, dont select it as mentioned in the below link rather deselect it and check

https://support.solarwinds.com/SuccessCenter/s/article/Enabling-64-Bit-Counters?language=en_US

Hope this helps.

Also remember that if these are Gig ports, they would need to send a pretty decent amount of traffic to see anything.  When in doubt, you can always go to the Performance Analysis and add in the individual interfaces to see if there's anything.

One last thing that I've seen.  People occasionally forget to include the performance metrics and are just monitoring for up/down.  Go to the node and select List Resources in the management widget.

Make sure that the interface traffic statistics are also checked (like below):