Mount.cifs with vers >= 2.0 isn't working

Hi all,

I have a turris omnia, OS 3.11.12 with NAS packages installed. I can mount cifs share with version 1.0:

mount.cifs -o user=X,password=X,vers=1.0 //qnap.lan/Nase /root/test

In output of mount I can see then:

//qnap.lan/Nase on /root/test type cifs (rw,relatime,vers=1.0,cache=strict,username=X,domain=QNAP,uid=0,noforceuid,gid=0,noforcegid,addr=,file_mode=0755,dir_mode=0755,nounix,serverino,mapposix,rsize=61440,wsize=65536,actimeo=1)

However, it won’t work with any higher version:

root@turris:~# mount.cifs -o user=X,password=X,vers=2.0 //qnap.lan/Nase /root/test
mount error(22): Invalid argument
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

I can mount that share with version 3 on my laptop, so I don’t think there’s an issue on the server side. Can you assist how to debug this more - or maybe I need to install something else?

Thank you.