WebDAV not working using Port 84

I cannot get WebDAV working. I am trying to use a different port, port 84. Is this even possible?

My seafdav.conf is as follows:

enabled = true
port = 84
share_name = /seafdav
workers = 5
timeout = 1200

I modified the file via docker as follows:
$ docker cp seafile:/opt/seafile/conf/seafdav.conf ~
$ vim seafdav.conf # make changes above
$ docker cp seafdav.conf seafile:/opt/seafile/conf/
$ docker exec -it seafile bash
root@xxxxxxxxxxxx:/opt/seafile# chown root: /shared/seafile/conf/seafdav.conf
root@xxxxxxxxxxxx:/opt/seafile# /opt/seafile/seafile-server-9.0.10/seafile.sh restart
root@xxxxxxxxxxxx:/opt/seafile# exit

The command “$ sudo netstat -tunlp” shows nothing about port 84.

I try to connect from my desktop using davfs2 as follows:
$ sudo mount -t davfs -o uid=$USER xxxxx:// /media/seafdav/

That prompts me for my username and password. I enter the same username and password as for my Seafile web dashboard. I get the following:
/sbin/mount.davfs: connection timed out two times;
trying one last time
/sbin/mount.davfs: server temporarily unreachable;
mounting anyway

When using with Joplin, a synchronization configuration check results in the following:
Error. Please check that URL, username, password, etc. are correct and that the sync target is accessible. The reported error was:
request to xxxxx:// failed, reason: connect ECONNREFUSED (Code ECONNREFUSED)

My seafdav.error.log is empty.