I figured out, what causes the problem: zammad can´t work with offce365 imap, when the system has ipv6 enabled.
Just disable ipv6 via net.ipv6.conf.all.disable_ipv6 = 1 - see https://www.faqforge.com/linux/how-to-disable-ipv6-on-debian-10/
I figured out, what causes the problem: zammad can´t work with offce365 imap, when the system has ipv6 enabled.
Just disable ipv6 via net.ipv6.conf.all.disable_ipv6 = 1 - see https://www.faqforge.com/linux/how-to-disable-ipv6-on-debian-10/