I'm going to solve my own problem here

I decided to try another CAT 5 cable from the POA antenna to the Adapter. 
And lo and behold, it connects. 
Odd as it was obviously receiving power but I guess there must have been broken or damaged 

  @www1 I can confirm that changing cables did help; thanks for the tip!

I wasn't able to load tplinkeap.net on my EAP-110-Outdoor. The devices couldn't obtain IP and were automatically assigned to the 169.254.X.X series. I tried placing this EAP on two different networks with working internet. The EAP was intermittently discoverable on Omada Discovery Utility in the network, the status light was solid green, and the EAP was broadcasting SSID. However, on connection, the DHCP IP assignment failed every time. I used Amazon Basics CAT-6 cables from switch to POE adaptor (as Data LAN) and POE adaptor to EAP (as Data + Power).

I replaced the data LAN cable from my switch to the POE adaptor with a CAT5E data-only cable. (I mean the cable which doesn't have 4 DC cables on the connector)