I'm out of ideas. I have this device and I can't log in! I type 192.168.1.1 and then I have to enter username and password, but I don't know, which username! It's not described neither in manual nor on device itself! I tried „admin” but it doesn't work! And when I reset this device, I have to enter new password, confirm it, then configure this device, but after reset I have again login and password fields! And after 3-4 attempts I see a message „You have exceeded ten attempts, please try again in 5678 seconds”. And even reset don't help! How the hell I can configure this device?! 
And why on login page is

AC750 Wireless Dual Band Router
Model No. Archer C20

if this is MR3020?!