I'm sorry to hear that. This is a complex case that we suggest you look for external help to recover access to the machine. As you don't have SHELL access to the server, you will need to stop the machine, mount the volumes in a different virtual machine and use a
chroot to access all the files of your old installation. Once you run the chroot command, you could change the bitnami user password using the
After that, you'll need to unmount those files and boot the old machine again. It's really important to mention that you can loose the data in case you don't perform all the steps correctly so it's strongly suggested to perform a backup of the virtual machine first.
This process will help you recovering access to the shell in the virtual machine and you'll need to reset the Redmine password after that. We suggest you ask in the official forums of the application to get more information about how to reset the password.
I hope all this information helps.