Here is the debug:
SSH: state machine state 5
SSH: got SSH2_MSG_KEX_DH_GEX_REQUEST msg
SSH: DH_GEX_REQUEST, bad parameters: their min 2048 > our max
SSH: their max 8192 < our min 1024
From here:
https://www.novell.com/support/kb/doc.php?id=7016904
A change was made to the openssh package, dealing with Diffie-Hellman Group Exchange. Previously, keys of size 1024 - 8192 could be exchanged. The minimum was raised to 1536 for added security and to avoid the "logjam" vulnerability. However, if used with some 3rd party ssh implementations which only support 1024, failure will occur. Ideally, the 3rd party ssh configuration or code should be updated to use larger key sizes.
I will try a FW update and see if that fixes it.
The DH group exchange max of 1024 on teh Digi is not longer accepted by the openssh client.
Cheers,
John