Hi,
LP teams are being deprecated. We recommend creating a Store account linked to your team via ie. an email alias or mailing list (the latter is not recommended, but easier) to register the charm under. An example email is in this previous request. I can then add you as a collaborator on the package, and you should be able to add the relevant collaborators from https://charmhub.io/dovecot/collaboration. If you wish I can also register the charm under your account and the account transfer can be done later. Let me know if you have any questions.
Thanks,
Deep