Non-Interactive ssh access fails

[zep_apc]

I am trying to obtain information from AP9630/31 NMC via cli. When doing this within an interactive session(e.g. putty) i am able to issue a command like "upsabout" and get values returned. When doing this within a plink session, i will not get a result but the session is being closed by the NMC. My current AOS is v 7.0.8.

I experience the same behavior when using CygWin and it's ssh client.

Doing the same with an AP9640 and AOS v1.5.1.1 it behaves as expected and returns results in key:value pairs. 

For authentication is use local accounts

Any similar experience and suggestion to resolve this?