Looking at logs, the issue seems to be that the LXD server is too old (probably 4.0.8, which is the default on focal):
Please upgrade your LXD host to 4.16 or higher to support the following extensions: custom_block_volumes
Looking at logs, the issue seems to be that the LXD server is too old (probably 4.0.8, which is the default on focal):
Please upgrade your LXD host to 4.16 or higher to support the following extensions: custom_ block_volumes