Ubuntu 18.04. I meant to click on eject and clicked on unmount. Now I can not use the DVD player. I tried reboot and I inserted and ejected the DVD a few times. Before when I put the DVD in it wound mount and display in browser and I could access the files on it. I have a Blu Ray player on same machine and it still works like this DVD drive used to. What do I need to do to fix this?
As your using Nautilus you can try enabling the auto mount option using the dconf command.
This guide tells you how to disable it so follow the instructions and make sure that automount is ticked..
How to disable automount in nautilus's preferences
There is a Linux command called lsblk which will list all of the connected block devices regardless of if they are mounted or not.
From there you should be able to obtain the device name and then eject/mount it.
e.g.
For adding in mount entries into /etc/fstab this link is very detailed..
https://www.cyberpratibha.com/use-of-fstab-option-for-mounting-disk-in-linux-permanent/
This one details automatic mouting of optical drives.
https://www.techrepublic.com/article/how-to-properly-automount-a-drive-in-ubuntu-linux/
Turns out it was user error. Wrong labeled disk. Said it was a DVD and it turns out it was a Blu Ray. There is a Blu ray drive on the computer but that was not the one I was using.