Even if you can extend portal network, you still need to go to the authentication page to login. The problem is when you type in username and password, it didn't work? Or you mean type in the admin...

170809 is EU version firmware, same as 170110. What's wrong with the 170809 firmware? I heard that new firmware is coming soon

contact tplink support to debug

you may need more powerful extender, or more.

The router just respond again automatically after some seconds? You may not be able to access 192.168.1.1 admin menu if ping fails, but try it. To see if you can check the info in Status window. Also...

the sticker only shows the hardware version. do you see hardware version too when you login management menu? I guess it will show version 2 as well. 3.0.0 Build 170103 Rel.02853 is the firmware...