are you loss your linux server root password and You can not log on to your server and your server in datacenter ovh or hetzner
don't worry
i will tell you step by step how to restore your root password ,
1- log into your datacenter control panel and boot your server in rescue mode
2- after your server booted see if your HDD is mounted or not (you can use df command)
3- if your HDD not mounted create new Directory and mount your / Partition
mkdir /root/myhdd
mount /dev/sda2 /root/myhdd
4- change you root directory
chroot /root/myhdd
5- Now You change your root Password :
passwd root
6- enter your new password and reboot server in normal mode
Have a Nice Day !