Folgende Antwort vom Support (vielleicht hilfts jemand anderen auch) - Drucker lässt sich jetzt starten:

The reason for the failure for the SNMP printer devices is because SNMPv3 ONLY support is provided in the base of 7.5.
In order for the existing LAN printer device descriptions to work, the ALLOW SNMPV3 SNMP attribute must be changed from *V3ONLY to *V3AGENT, *YES, or *NO. The recommendation is to set it to *V3AGENT:
CHGSNMPA ALWSNMPV3(*V3AGENT)


After making the change to the SNMP attributes, restart the print writer.