Error when trying to copy a container to a remote

Hi everyone,
I used to have two servers with LXD installed via apt managed to configure them so that I could lxc copy from my main server to the one I wanted to use as a backup host.

I then found out about incremental copies and that I would need a more recent version of LXD to use them, so I migrated both servers to a snap installation of LXD. I re-configured the remote and am back to a state where I can list the remote containers from my main server.
However, lxc copy is no longer working, neither with nor without the --incremental flag.
The error message is
Error: Failed container creation: Error transferring container data: exit status 23.
I already found out that this is an rsync error code and looked in the lxd.log to find out more.
There, I can see the line
t=2019-08-25T22:54:48+0200 lvl=eror msg="Rsync send failed: /var/snap/lxd/common/lxd/snapshots/blog/backup/: exit status 23: rsync: change_dir \"/var/snap/lxd/common/lxd/snapshots/blog/backup\" failed: No such file or directory (2)\nrsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1183) [sender=3.1.1]\n"

It seems that /var/snap/lxd/common/lxd/snapshots contains symlinks for each of my containers, e.g.,
lrwxrwxrwx 1 root root 56 Jun 2 23:36 blog -> /var/lib/lxd/storage-pools/lxd/containers-snapshots/blog
for the one related to the error message above. However, /var/lib/lxd/storage-pools/lxd/containers-snapshots/ seems to be missing. Underneath of /var/lib/lxd/storage-pools/lxd there is only a folder ‘containers’.

Could this indicate an error in the migration process? I can still create snapshots and list them.

Nobody who could help me shine some light on my problems here? If there is more information needed, I am glad to provide anything that might help to resolve this issue. It would be great if I could finally use the incremental snapshot + copy feature as an improvement to my backup setup.

After you have migrated successfully, you should not see any references for files in /var/lib/lxd/.
I suppose you run on both servers sudo lxd.migrate and completed the migration once you installed the snap package of LXD.

This case is straight for bug report on Github.
Have a look at to check whether it is the same issue.
If not, file a new issue on Github. Use as a guide this report.

Thanks for helping out @simos. I finally found the time to get back to this issue.
As I rarely find the time to work on this, I don’t really feel comfortable to make a Github issue out of it.
Yes, I could confirm that I did run ‘‘sudo lxd.migrate’’ by checking the history. However, I can’t really tell anything else.
It has been weeks, if not months, since I did the migration and so I don’t remember either of the versions of lxd involved. I also have no idea how this could be reproduced and no way to easily roll back my server.

Is there any way I could manually finish what lxd.migrate seems to have forgotten? Would there be any harm in just running it again?