I've configured SSH server on the router according to the following document:
Configuring Secure Shell on Routers and Switches Running Cisco IOS
Result - I'm unable to access to router's vtys using SecureCRT SHH client
Debug 'debug ip ssh' shows the following:
Jul 17 14:10:23 MSD: SSH: throttling requests: Please try after some time
Searching the web doesn't return anything useful. It seems that this type of error message doesn't exist on the internet.