I have upgraded the L3 Switch to latest official (recommended -> Feb 2015) IOS, without success.
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 28 WS-C2960XR-24TS-I 15.0(2a)EX5 C2960X-UNIVERSALK9-M
I'm able to connect only if I use sha1 instead of sha2 or if i use an older (I think 4.86) ttxssh.dll.
From what i see this error "DH_RANGE_FAIL: Client DH key range mismatch" it is very popular.
The bug was addressed to CISCO please follow below link:https://tools.cisco.com/bugsearch/bug/CSCuo76464
I have also tried few of the ideas regarding "KexAlgorithms", without success, at least until now.
Therefore is the error on which Yutaka was referring in the first place.