Glusterfs snapshot failed

[bakonyip]

Hi,
I will use glusterfs snapshot for backup my volume. I write this command in glusterfs pod.
gluster snapshot create snap-testvol testvol
And after 1 min loading is say:

Error : Request timed out
Snapshot command failed

I used latest glusterfs docker image, gluster version is:
glusterfs 4.1.7 Please help me, how to fixed my problem and use gluster snapshot feature?
Thanks, Peter