@Season 

Hey and welcome!

I think I know what is going on here, will take some fiddling at your side to get it working so let me explain

Basically when the controller moved from version 3.2 (which you have running) to v4 and now v5 it required new firmware for all devices, the EAP245 included.  The older firmware for v3 controller is something like 2.4.0 if memory serves me right..  on a v4 or v5 controller you will need to manually upgrade the APs firmware to the new version (5.0.6 is latest).  This wont upgrade automatically via the controller to stop it auto-updating and busting all round the place.   In short when you decide to move to v4 or v5 controller its a total manual update of the controller.   

Before you upgraded to the new v5 did you forget the devices?     Its also best to reset the AP, found it easier to adopt after a reset.

The best thing to do would be forget the APs in your current v3 controller and reset them.  

Then upgrade the controller to v5 and readopt the EAP245s post reset

Once Adopted, setup SSID etc etc then enable MESH under Settings, you should then see the EAP225 for adoption.  

Hope that helps!

• What is the reason that the EAP225 is not visible to the root AP / controller?

Either MESH is not enabled in settings, or the controller v3 doesnt support it.   You do need to update your controller for the AP firmware you are running

• Why are the newer software controllers not seeing the wired AP's?

Try a reset on them, they should just adopt in automatically.  

• Am I using the wrong software controller? But I tried different versions with a different outcome (newer once can't even detect anything)

Yes you are.  The APs firmware (5.xx) is designed for v5 controller.   It will also be easier to setup mesh on  v5

• Are the firmwares not the right ones?

APs are OK from what you say..  controller is needing updated

• Do I really need to use the hardware OC controller? Is it this that I'm missing? Because at the moment I only use the Omada software controller

Are you running this on a Windows Server???   disable the firewall for bit.   The new v5 controller uses different ports vs the v3 and adoption may be blocked by it.   That might be your issue there, some firewall (windows or 3rd party).   In answer to question, not really its personal choice.  The Software controller is fine if you have a decent server to run it on, no issue there.

  @Philbert 

Hi Phillbert,

Thank you very much for your reply. I really appreciate it!

Following your advice I did the following:

1. I've reset the AP's and adopted the AP's in the V3 controller
2. upgrade the AP's firmware to the new versions manually (using the V3 controller). Afterwards both the EAP245 were disconnected and couldn't be seen on the Omada controller V3 anymore. I assumed the V3 controller doesn't support the newer firmware and that's why it is not visible to this controller anymore.
3. So, I uninstalled the V3 controller and installed the V4 controller
4. After landing on the dashboard of the V4 controller, I went to the "Devices" page to look for my AP's

Results:

- Now i can't see any AP's anymore. Not even the wired once now:'(

- I've reset the AP's to see if it will detect. But still no sucess

- Also tried with the V5 controller, AP's nowhere to be seen

I really don't understand why it doesn't work. I must be still doing something wrong I suppose???

  @Season 

You are best going to the v5 controller as its got a lot of new features, going through this pain its likely the best option for you in the long run

In terms of not seeing the APs.. this smells of Firewall or ports, especially if you are going via a switch.

Try taking the firewall off on your server and see if that helps, saying this as it's the most common issue with the software controller on a windows device.   Also, the ports have changed since v5 and are not the same as they were in v3..

More port details here if that helps, deffo would be looking there first if in your position.   In terms of controller, update or new install?   New install may be the best option here

https://community.tp-link.com/en/business/kb/detail/362

  @Philbert 

Hmm...

The firewall could indeed be the issue.

The controller is starting up fine. So, does it mean that some of the ports are being blocked probably??

I will take a look and experiment the next weekend.

I will let you know the results.

Thanks for the help and have a nice weekend!!!

  @Season 

Yeah its a common issue that firewalls block the ports.    Firewalls generally only allow traffic on the more common ports (email, web, etc etc) and these are less than 1024, the ports for AP communication is in the 28000 odd range.

Best thing to do is temporarily turn it off and test, its a common complaint we see on here, especially on Windows Servers