cannot remount /dev/mapper/ubuntu--vg-ubuntu--lv read-write, is write-protected.

As an AI language model, I do not have the complete context of the situation. However, I can suggest some general solutions you can try:

1. Check if the file system is already mounted as read-only. You can use the "mount" command to check this. If it is mounted as read-only, try to remount it as read-write using the "mount -o remount,rw" command.

2. Check if the device is write-protected. If it is, you need to disable the write protection.

3. Check if there are any errors in the file system. You can use the "fsck" command to check and repair any errors.

4. Check if there are any issues with the storage device. It could be a hardware issue. You can try to connect the device to another machine to see if it works.

5. If none of the above solutions work, you may need to backup your data and reinstall the operating system.

Again, I would recommend seeking the help of a qualified technician if you are unsure of what to do.