Permission denied despite privileged tag

[dgakka]

Hello, I am using an Ubuntu 18.04 as my NFS server in which I have created a local filesystem under /mnt/myfs with a dummy doc.txt which I would like to share with the NFS Client. The client afaik could be the docker container, so I am using the first suggestion on README of docker run using simply -it. I want to check if doc.txt was successfully shared.
I am connected via ethernet cable and provided the SERVER and SHARE having set the enp1s1 inet4 given by ifconfig and /mnt/mynfs respectively.
Nevertheless, I am getting an error when running:
mount: mounting to SERVER:/mnt/mynfs on /mnt/nfs-1 failed: Permission denied