How to troubleshoot SSH error on cisco router

Error %SSH-3-PRIVATEKEY Unable to retrieve RSA private key

Feb 24 2011 14:39:56.539 TH: %SSH-3-PRIVATEKEY: Unable to retrieve RSA private key for R4.ruamit.co.cc
-Process= "SSH Process", ipl= 0, pid= 4
-Traceback= 81037CC0 81034670 81035D38 8020D9E8 8021117C
Feb 24 2011 14:39:58.963 TH: %SSH-3-PRIVATEKEY: Unable to retrieve RSA private key for R4.ruamit.co.cc
-Process= "SSH Process", ipl= 0, pid= 4
-Traceback= 81037CC0 81034670 81035D38 8020D9E8 8021117C
Feb 24 2011 14:46:05.540 TH: %SSH-3-PRIVATEKEY: Unable to retrieve RSA private key for R4.ruamit.co.cc
-Process= "SSH Process", ipl= 0, pid= 4
-Traceback= 81037CC0 81034670 81035D38 8020D9E8 8021117C
Feb 24 2011 15:02:01.306 TH: %SSH-3-PRIVATEKEY: Unable to retrieve RSA private key for R4.ruamit.co.cc
-Process= "SSH Process", ipl= 0, pid= 4




Resolve By solution below

1 - Remove ssh or disable by command " crypto key zeroize rsa"
2 - Generate key again by command " crypto key generate rsa"

If still cannot login ssh check by command " sh crypto key mypubkey rsa"
and chose key to used by command " ip ssh rsa keypair-name "

sample error when login

root@ssh-server:~$ ssh -l cisco 192.168.1.1
Disconnecting: Corrupted check bytes on input.
root@ssh-server:~$


example

R4#show crypto key mypubkey rsa
% Key pair was generated at: 00:04:12 UTC Mar 1 2002
Key name: R4.ruamit.co.cc
Usage: General Purpose Key
Key is not exportable.


key name is R4.ruamit.co.cc

router (config)# ip ssh rsa keypair-name R4.ruamit.co.cc