@LeoRodriguez 

Since making the change on your router, was the wireless network forgotten then connected back so you are prompted for the wireless password again?

If you use a WiFi analyzer (app on your smartphone) does that indicate WPA/WPA2 still?

@Tony 

Yes, I did it, but after a while, the warning did appear again. Actually, I've decided to come back to my first router, I tested the coverage/speed with the Archer and it was awful, many of my devices started to navigate very slow (from 180Mbps to 15~20Mpbs).

I didn't try with wifi analyzer. For now, I'll continue using my other router. Honestly, I'm very disappointed with the Archer C5. Perhaps I'll connect it again to test, Thanks!!

@Tony Hi! According to App Wifi Analyzer, the security is wpa-psk-ccmp+tkip (1st image), but the router is configured as follows (2nd image)

Any firmware update?