Make sure that Cakey Bot has the
Manage Rolespermission and that the Cakey Bot's role is above the roles it is trying to assign.
Persistent Roles will auto-assign the given roles to a user when they rejoin your server. This can be excellent on VIP, Staff or Mute roles.
To add/remove a persistent role from a user you can use the
/role persistent <user> <role> command.
After you have added some persistent roles to a user, they will be automatically applied to the user when they rejoin your server.
A common use case for persistent roles is to automatically re-apply a mute role when a user leaves/joins the server to try and get rid of the mute or bypass it. If you use Cakey bot's mute command (
/mute <user> <reason>), they will NOT have the mute role added as a persistent role. You will have to run the persistent role command separately OR you can enable "Persistent Mutes" on the moderation section of the web dashboard to have mutes added as persistent roles automatically.