@Virgo 

Thank You for the response.
 

Did the EAP obtain a valid IP? Yes, I can see their local http landing page stating it is being managed the omada controller.

Have you checked VLAN settings in your network? Yes, when working on the 670 or 615.  The vLANs work as expected. 
 

If the EAP110 is used in standalone mode, can it work? I believe standalone mode is mutually exclusive from Omada Controller.  Since it is controlled by a controller, I do not think standalone is possible.  In any case, it is adopted to the controller and has same settings as all other APs.

Have you tested the cables?  Yes.  2 different cables to 2 different 110s have the same issue.  I have tested by putting a 615 in their place.  And the 615 works as expected.
 

You can also set a separate SSID for EAP110, check if the clients can see it and connect to it:  Yes, I tried this yesterday.  Unfortunately, more of the same.  I did not create a seperate WLAN group... I'll try that later.