LXD 3.15, Same issue, same error msg, and same solution as simos.
Sidenote: The number-thingy was a file on my system, not a dir like it was for simos:
rm /var/snap/lxd/common/lxd/database/global/7133-7217
@freeekanayaka , do you want a copy of database/ ? If so, I’ll send it to the canonical email.
Thanks all!