Purging with GYB purges the wrong mailbox

[mvmaastricht]

First of all a GREAT thank you to the GAM team for developing GYB! I'm using it to migrate emails of old nameless IMAP accounts from our provider (like [email protected]) to equivalent Google Groups in Google Workspace. I do that with a special account account I created for this: [email protected]. I installed GYB from the admin account [email protected]. I want to use the following steps:

1. Import email from an external IMAP account into the [email protected] Workspace account;
2. Use GYB to migrate the email from [email protected] to the corresponding Google Group;
3. Use GYB to purge the [email protected] account;
4. Start over with step 1.

However, the purge command wipes the admin account [email protected] in stead of the account [email protected]...
I've use the following command:

gyb --email [email protected] --action purge --use-admin [email protected]

What did I do wrong?

Oh, and by the way: if I use gyb --email [email protected] --action purge --use-admin [email protected]

I get:

Got 284 Message IDs                                                             

403: Insufficient Permission - insufficientPermissions

EDIT: in the meantime I discovered that I failed to give the right access to the migrate account (reading only). After revoking access from the account itself, I wasn't be able to regain access: kept on getting

ERROR: ('invalid_grant: Token has been expired or revoked.', {'error': 'invalid_grant', 'error_description': 'Token has been expired or revoked.'})

After trying lots of times, I deleted the migrate account completely and created a new migration account. After giving full access, I was able to purge with the command

gyb --email [email protected] --action purge --use-admin [email protected]

(so using --use-admin [email protected] which is not the admin account...)

So my first question remains: why did GYB purge the admin account, while leaving the migrate account untouched?