Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:SeaEagle1:CourierMTA/openSUSE_Tumbleweed/home:SeaEagle1:CourierMTA.repo
zypper refresh
zypper install courier-authlib
Для openSUSE Slowroll запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:SeaEagle1:CourierMTA/openSUSE_Slowroll/home:SeaEagle1:CourierMTA.repo
zypper refresh
zypper install courier-authlib
Для 15.4 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:SeaEagle1:CourierMTA/15.4/home:SeaEagle1:CourierMTA.repo
zypper refresh
zypper install courier-authlib