Juniper devices that Network Configuration Manager (NCM) supports out-of-the-box are not automatically placed in the Juniper JUNOS device family.
a) Device does not support SSH v2
b) Device is not certified in Spectrum, it was modeled as GnSNMPDev (Generic SNMP Device)
a) Network Configuration Manager supports SSH v2 only. Network Configuration Manager does not support SSH v1. Juniper devices that do not have SSH v2 enabled are not automatically placed in the Juniper JUNOS device family.
b) Either upgrade the Spectrum release to the certified release or perform the self-certification.
Please reference the "SSH v2 Support" section of the documentation for more information.