Configuring Nextcloud Mail with Default Folders

I have a Nextcloud (v22.1.1) container running on Docker. The Docker host is an Arch-based rolling distro, so I’m not sure if I can give a version number for it. The container image is nextcloud:latest, which comes with Apache web server by default. The Php version is 8.0.11 .

I have two Nextcloud accounts that I’m trying to setup with the Mail app. One account is a native Nextcloud account, and the other is from an AD/LDAP server. The mail server is a new hMailServer instance, on the same network as the Docker host. Both accounts encounter the same issue:

After connecting an e-mail account successfully, they can view the Inbox and Receive new messages. But they can’t Send or Delete messages. When attempting to Send messages, they get the following error:

No sent mailbox configured. Please pick one in the account settings.

When I first saw this error, I created new folders under both e-mail accounts (DRAFTS, SENT, TRASH). But, when I went to configure the folders in Account settings, under Default Folders, the config page can’t see the folders that I created. It can only see INBOX, for both accounts.

Other e-mail clients can supposedly create the folders required as the need arises. Does Nextcloud Mail have this functionality? How should I go about creating and configuring the required folders?

The issue resolved itself while I was out. No idea what happened to resolve it. I’m now wondering why it took hours to detect the folders…