RB750gr3 rebooting

Hello, i recently bought a RB750gr3, made the initial configuration and everything was working fine. After that, i tried to upgrade firmware to the most recent version 6.44.2, its when my issues began.

The RB keeps rebooting, not even allowing time for acess. I tried netinstall and downgrade to the long term version, the rebooting stopped but the RB didnt appear on winbox. So i tried again netinstall following step by step the MikroTik Wiki, the procedure worked fine but the RB is again on reboot loop.

Someone can help me?

Thanks

This is not normal behavior. Change it back for a new one.