Problem when installing OpenWrt on TL-WA850RE

Hello everyone,
I'm using TP-link repeater WA850RE (EU) Ver 1.26. Today, I have tried to install OpenWrt in this link: So after install this fimware on my repeater, I can not access to to config. Then I have tested with cmd, the repeater still respone. Moreover, I pressed RESET button with believe to access Failsafe mode in this link: to reinstall but it failed.
Can you tell me some possible solutions?
Thanks so much. I'm so grateful.
this is an image to tell you more about my problem.

It won't work by default with https. Try with http first and then you can enable https.


Thank you for answering me, and I have tried as you said, but I failed again.
Here is the screenshot for you.

The image you used is a snapshot. These don't ship with Luci, you'll have to SSH into the device and install it manually.