Changed permissions of docker volumes folder > You don't have permission to access this resource

I am running an instance of nextcloudpi in docker. I wanted to sync the data folder between two server via rsync, but got a permission folder. So I tried to give my user "John" the permission to read the folder. It seems I did something wrong as know the instance cannot access the data folder and in the browser when trying to access nextcloud, I get "You don't have permission to access this resource." Can someone please tell me how to fix this? What should the permissions in the folder are? Right know, I have the following permissions:

$:/var/lib/docker$ sudo ls -l
drwx--x--x 4 root root 8 Mai 28 20:09 buildkit
drwx------ 3 root root 3 Jun 17 18:25 containers
drwx------ 3 root root 3 Mai 28 20:09 image
drwxr-x--- 3 root root 3 Mai 28 20:09 network
drwx------ 4 root root 4 Mai 28 20:09 plugins
drwx------ 2 root root 2 Jul  2 17:14 runtimes
drwx------ 2 root root 2 Mai 28 20:09 swarm
drwx------ 2 root root 2 Jul  2 17:14 tmp
drwx------ 2 root root 2 Mai 28 20:09 trust
drwxr--r-- 3 root root 5 Jul  2 17:14 volumes
drwx------ 3 root root 3 Mai 28 20:10 zfs

$ sudo ls -l volumes
total 7
brw------- 1 root root 0, 64 Jul  2 17:14 backingFsBlockDev
-rwxr--r-- 1 root root 32768 Jul  2 17:14 metadata.db
drwxr--r-- 3 root root     3 Mai 28 20:11 ncdata

To avoid permission issues, I would recommend using linuxserver.io's NextCloud image. Here you can set the PGID and PUID easily in the docker or docker-compose configuration file.

For instance, if the PGID and PUID of John is 1000, just use the default value.

Generally, for the data for each container, you should have the following permissions:

• For files: -rw-r--r-- 1 John
• And for directories: -rwxr-xr-x 1 John

Also, did you add the user John to the docker group? Use this command:

sudo usermod -aG docker John

Confirm with the groups command, that you're a member of the docker group.