ok, how could it lead you to the router's website, just two reason. First, you don't reset it rightly. Second, you don't connect to the TP link device directly. Refer this:...

It would better that you should uninstall the controller 2.2.3 then install the controller 2.0.3. There are not downgrade option like the EAP firmware. So you need to install controller again.

ok, i think you could reset your 901ND first, then refer this faq: http://www.tp-link.com/en/faq-375.html. After you could login in, you should set static ip for your 901ND, don;t forget set the...

After you use 901ND connected to your router with cable, the ip address of 901ND is changed then you need to check from your router. If not, you may need to set static ip for your 901ND. For the slow...

If your server is offline, it truly would be disconnected. If IP address of your server which install controller won;t change, you EAP would connect to the controller again. EAP could remenber the IP...

For reset process you need to notice that you should click the reset button for 10s and you could see all light flash on and off. Then refer this FAQ: http://www.tp-link.com/en/faq-931.html