Hi Michael,
finally, we’ve solved the issue (without dirty workarounds).
As you said, we set the SNMP v3 settings to AuthNoPriv:
The root cause of the problem was not the password, but the authentication protocol in Checkmk.
I usually use SHA. But that doesn’t work here. MD5 has to be choosen:
Now it works properly…
Thank you and kind regards,
Antje