unable to mount cifs file system

I am using openSUSE Leap 15.1

In the past the following command

sudo mount -t cifs -o user=pschmitt //192.168.178.1/fritz.nas /media/fritz-nas

succeeded without problems.

But now this command returns

mount error(2): No such file or directory
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log
messages (dmesg)

dmesg | grep cifs
[ 937.787720] FS-Cache: Netfs 'cifs' registered for caching
[ 937.789474] Key type cifs.spnego registered
[ 937.789477] Key type cifs.idmap registered
[ 8656.242922] CIFS VFS: cifs_mount failed w/return code = -2

I tried
smbclient -U pschmitt -L 192.168.178.1/fritz.nas

and received
Unable to initialize messaging context
Sharename Type Comment
--------- ---- -------
FRITZ.NAS Disk
IPC$ IPC IPC Service (FRITZ!Box)
Reconnecting with SMB1 for workgroup listing.
Server Comment
--------- -------
Workgroup Master
--------- -------

I have checked related questions in LinuxQuestions but did not find a clue.
How can I identify the problem and solve it?