Looks Like Permission issues. I used a combination of this video from rock Star Techno Dad Life and this comment by
https://www.youtube.com/watch?v=f1aOiFtBG3Q&t=82s
Hi guys !! A quick note/update: in OMV 5 the command "omv-mkconf" is no longer working (deprecated). The new syntax for the command used in this video is "omv-salt deploy run fstab". Don't forget to Sudo. Basically omv-salt replaces omv-mkconf for this and other commands.Check out the documentation and the forum for more info !!Be good !