"Architecture" error while moving lxd 2.0 container to new server lxd 3.0.3


I have one server with disk partitionned. One partition is running ubuntu server 16.04 with lxd 2.0. I just installed on second partition ubuntu 18.04 with lxd 3.0.3.
I would like to move my containers from present server to new one.
Of course, both servers can’t run at the same time. If needed I can access files of the other partition however.
I tried the procedure given by Stéphane Graber here Backup the container and install it on another server
But when I tried to run lxc launch bck-container newcontainer I have this error :
Error: Requested architecture isn’t supported by this host
On a newly created container lxd3 , I can see its architecture is “i686” whereas in lxd2 container, it is “x86_64”.

Is it possible to do what I want ? How to proceed ?


Can you show “uname -a” on the new server?

New server :
Linux srv1 4.15.0-64-generic #73-Ubuntu SMP Thu Sep 12 13:15:53 UTC 2019 i686 i686 i686 GNU/Linux

Previous server :
Linux srv1 4.4.0-164-generic #192-Ubuntu SMP Fri Sep 13 12:02:50 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

From what I understand is that x86_64 is true 64bit and it is the proper target for the OS. I should have paid attention to that when installing.
And I suppose there is no way to convert to x86_64. I guess I have to reinstall…

Considering I have 4 GB on my Brix, it does not seem to be appropriate or worth to change it to 64bit.

Sorry for inconvenience as not related to lxd.