How To: Incoming Mails in OpenProject 9.0


i want to use the feature of generate work packages from mails in OpenProject 9.0.

I already edit the file /var/lib/univention-appcenter/apps/openproject/openproject.env so that i add the env variables IMAP_SSL, IMAP_PORT, IMAP_HOST, IMAP_USERNAME and IMAP_PASSWORD.
As it is shown here:

But there is nothing happening.
Maye someone can helb me? Maybe there is a logfile?