The distributed firewall is not in use or there are exclusions for the participating VMs.
When setting up a Logical Span port mirroring configuration, no mirrored traffic is seen at the destination.
The backing segment for the source and destination are using an overlay network.
The VMs have nics/ports connected to the segment.
Under the Logical Span Source column. The Status shows as Failed:
Click on the 'Failed' link. The following is seen:
Object Status: Success
Binding Status: Failed
Binding Status Error(s):
Destination ports must in same logical switch for logical SPAN
Clicking the refresh icon next to the 'Failed' link may change the Status to Success but the error returns after the window is closed.
NSX 3.x
NSX 4.x
VMs with connections to multiple networks/logical switches cause the config to fail.
This is true even when the VM has one nic connected to the correct segment but another nic connected to a different segment.
NSX requires the VMs in the groups to have their nics on the same logical switch for a Logical Span Port Mirroring config.
Connect the Source VM nics to one network.
Select VM inventory groups that contain VMs that meet the requirement. Note that one VM with multiple networks in a group can cause the Source config to fail.