We can reproduce the issue with SOGo 5.5.0.

What seems to be missing is the "e" (expunge) ACL flag, that is not set by SOGo when activating the "Insert, copy and move mails into this folder" and "Erase mails from this folder" access rights on a folder.

Steps to reproduce

1. We set the access rights as shown in the attached screenshot (rights are set for //user1@example.com// on the //user2@excample.com// INBOX folder)
2. //user1@example.com// tries to move an email from //user1@example.com//'s INBOX folder and gets an //access denied// notification in SOGo (and any other mail client like Thunderbird)

Current workaround

Set the "e" (expunge) IMAP ACL flag manually. For Dovecot:

doveadm acl add -u user2@example.com INBOX user=user1@example.com expunge

After setting the "e" flag, user1@example.com can move mails from user2@example.com's INBOX folder without any issues (using SOGo or any other mail client like Thunderbird)

I can't reproduce the issue. If I select the Expunge this folder right, it properly gets updated on the mailstore (Dovecot):

# doveadm acl get -u sogo1 INBOX
ID         Global Rights
user=sogo2        expunge insert lookup read write write-deleted write-seen

After some research it does not look like and ACL issue, but just a misleading translation of the phrase //Expunge this folder//.

In ''UI/MailerUI/German.lproj/Localizable.strings'' it translates to //Diesen Ordner komprimieren//. But that actually means //Compress this folder//, which is a little bit confusing, i guess.

A better translation would be //Diesen Ordner leeren// or - when taking the real meaning of the ACL ''e'' flag into account - //Gelöschte Mails im Ordner endgültig löschen//.

Please join the Transifex team to contribute to the translations. Thanks!

//Diesen Ordner leeren// is plain wrong, as it literally means //Empty this folder//.
We use //Diesen Ordner komprimieren// because the same function in Thunderbird is called //Komprimieren// in German. since more than 15 years.
//Gelöschte Mails im Ordner endgültig löschen// would be correct and better understandable for new users, but much longer than the current setting.