I wanted to add another device to the MAC-whitelist when I recognized, that I cannot enter the web-interface anymore. I tried http as well as https with ending up in a timeout. I even tried the config tool. It found the device with it's correct IP-Address leaving me with no further options. So after countless attempts from other devices with different OS I decided to make a factory reset. This done, I tried to acces the device using the default wi-fi printed on the back of the device. Both networks showed up, the 2.4 and the 5 GHz. However there was no chance to connect to any of these networks. On Linux Mint it tries to connect forever without success, on Win10 I get a timeout after a while. So I tried to access it via ethernet. I set my computer to dynamic address configuration and connected the device (I used the POE-adapter because I lost the power supply - or there never was any). But the address tplinkeap.net is unreachable (yes I tried both http and https). After vainly searching the internet for a default IP-address of the acces point, I gave up eventually.
So my question is: is there another option to force access to the device (maybe commandline tools or whtever) so that I can at least try a firmware-update that hopefully may fix this? The device itself is about 3 years old.