Hello paud,
okay I try to give you a short overview:
List current mounts: mount -l
Have a look into the automount configuration file fstab: cat /etc/fstab (you should find the M2P mount at the end of the output)
Add a comment sign # to the line and save it (use the command: sudo nano /etc/fstab to edit the file).
Afterwards reboot and try to mount the share manually to see if you get any errors.
sudo mount <last line of fstab>
Greetings
Markus
