Not able to reset root password in debian based linode server

Question

The steps I followed: 1)Unable to login through ssh as well as Lish console........... 2)Tried resetting password from the cloud manager and successfully changed but not reflecting while login..Still showing incorrect password......... 3)Booted to rescue mode and done chroot to the disk 'passwd user/root' command is not working... getting 'passwd:Authentication token manipulation error'............. 4)to resolve the above error remounted the disk with read and write access-not working.............tried 'pam-auth-update' and got another error.this error message can be seen in the attached screenshot......... I am new to Linode environment and also to Debian 10 I am not able to solve this by resetting root password.is there any way to solve this without rebuilding the account???? Appreciate your help!!!