Inherited system with LAG question

So, here is what I inherited. I have a few questions about LAG.

Can't post actual configs as they are on closed network.

I have one fabric (R and L) containing Dell M6220's going to 2 ports on a Cisco 3750

Gi1/0/17 and Gi2/0/17 are configured to in channel-group (1) and are active when you do a show running config.

Now, when you throw in a show interfaces port-channel 1 command, it lists both ports but Gi2/0/17 is inactive.

When looking at the HW, no link light for the Gi2/0/17 port and nothing on the 3750 port for that connection. Gi1/0/17 is green on both ends (to include the 3750 connection).

Why would the Gi2/0/17 connection be inactive? Not all that familiar with LAG.

Thanks!