Ring doorbell Pro keeps restarting and never goes to configuration

Hi, I'm having problems with my refurbish ring doorbell pro. In first I tried with a transformer that I had that was 16V, then I bought a 18v on Amazon that was saying that worked just fine: https://www.amazon.com/dp/B07SL49GTH/?coliid=I33ODUQA7SI5PU&colid=1JT5VPFE8K16U&psc=1&ref_=lv_ov_lig_dp_it then after changing I Still can't go to the configuration mode... I left 2 days on, and the thing is that he start blinking the top blue, blink like 8 times, then stops, i can hear really close to him the sound like it was turning power off then the power on, then start blinking the top blue. I think my doorbell pro its broken.. because I already tryed to reset several times... and nothing happens.. if I click on the certer button it sound like I was ringging the bell, then blinks the white led all circle, and after 10 sec. turn off and then starts blinking the top blue again... I tested with the voltimeter, and says 18v. What I'm doing wrong or its a bad doorbell and need to be replaced?