Miscofiguration of /etc/passwd

Hello, I am new here. My issue starts trying to modify user permission to be root group, I tried modifying that user but seems as the new expertise in here I crashed my account... Context: I have my WHM with godaddy and created a cpanel which was working ok. How crash? I cant enter to user1 cpanel via credentials, it accepts em but throws me back to login, ftp throws me wrong credentials, email via outlook throws me wrong credentials. In opposite side, user2 cpanel (another site) loads fine and perfectly. Is there any solution for me? I wrote it too general? Thanks in advance...