Nzbget: permission denied

hi guys,
I used eekfonky’s guides to install nzbget, couchpotato and sonarr via docker to my pi.
I mounted a folder on my external hdd using this guide ( https://www.htpcguides.com/properly-mount-usb-storage-raspberry-pi/ )
but when starting nzbget, it tells me it cannot create folders…permission denied…any idea?
please tell me what part of the code I need to post to be helpful.
thanks!

this is my fstab
/dev/mmcblk0p1 /boot vfat defaults,noatime,noauto,x-systemd.automount $

rootfs is not mounted in fstab as we do it via initramfs. Uncomment for remou$

UUID=DC29-836E /media/hdd exfat nofail,uid=osmc,gid=osmc 0 0

On OSMC, external USB disk drives are automatically mounted under the /media directory. No need to mess with /etc/fstab.

Ok. I was under the assumption that this was necessary for nzbget, sonarr and CP to work correctly.
Anyway, the mount works, that’s not the issue. the problem is that nzbget cannot write to the disk due to write permissions I suspect.
Or does that perhaps have something to do with this “double mount”?
On my own raspi, this works perfectly. With my setup, it took ages to get nzbget and sonarr to work, but write permissions were never the issue.
Now, I am making a similar setup for a friend.
This time, all programs got installed and worked within 15 minutes, but I cannot write to the disk. Very strange.