@Parker00786 

Hi Woozle, 

After playing around with the settings, seems like the WPA3 Passkey Protection was the issue, changed it to WPA2 and all seemed to be fine and working. 

The following day, WIFI network showed to be connected and secured but any web page I opened up refused to load. Even trying to log back in to the Webconfig was an issue. 

Ive been factory resetting the router almost every day now, worse case scenario would be to buy a 30m ethernet cable to plug the extender directly in to the router. 

If youve got any other recommendations to try, it would be most helpful. 

Just as a side note, ive attempted setting the IP to static with details provided from the ISP but to no avail. 

  @Parker00786 

"... to buy a 30m ethernet cable to plug the extender directly in to the router."

If you would need a 30 m long cable to connect the TL-WA855RE to the router tells me that the two must be quite some distance away from each other.
Propagation of Wi-Fi signals inside buildings is quite limited. Of course, it depends on the structure of the building, but generally I would say that anything over 15 m is pushing it.
I would move the TL-WA855RE nearer to the router and see if that helps.

  @woozle 

Apologies for the mistype as well as the lack of clarity on my part. 

Actually meant a 20m cable. The extender is about 4 to 5 linear meters away from the main router but taking in to account running the cable along the 90 degree bends, up and around the door frame etc, the estimated cable needed would be about 16 to 17 meters. There is only one wall between the main router and extender for reference so signal coverage shouldnt be an issue (I get full wifi signal bars off the extender when sitting in my office)

The extender seems to act up whether im bordering the edge of where the extended wifi signal ends or whether im right next to it. 

Not sure how else to phrase this besides in laymans terms but could the Extender just not be smart enough to communicate with the Enterprise Router?  

  @Parker00786 

If it's only 5 meters, then the distance should be no problem. You can always check the signal strength of the connection between the TL-WA855RE and the Mikrotik router in the TL-WA855RE's admin webpage. (in the "Status" or "Network Map" screen click on the "Router" icon)

Just because the Mikrotik router is called enterprise router doesn't automatically rule out using a range extender. It would only become a problem if certain enterprise features are used that conflict with the workings of these simple range extenders.