Why's that not why's that not connecting with router

Hallo Rin bis zweimal am tag leuchtet der blaue Ring auf dem gerät rot, warum ist das so ?

I have a new modem but I can't connect my tp-link range extender. I've tried resetting the unit and have followed the set up steps on the app. However when I search for the unit nothing comes up?

My device is restarting automatically even after resetting it.Please help me.

2.4ghz and 5ghz (1) work fine problem is the 5ghz 2 random stopped working nothing can connect or detect it, tried turning on/off, checked firmware for updates, checked settings to make sure it's on a

2.4ghz is missing from the list of available networks. After months of smooth operation, 2.4ghz suddenly went missing. Its still enabled on the UI. Have already tried the following: - made sure 2.4ghz