Remove the suffix from your chained Action name, from this
<result name="success" type="chain">login.action</result>
to this
<result name="success" type="chain">login</result>
Note that Action Chaining is not recommended, Redirect Action or some other ways should be preferred.
From the official documentation:
Don't Try This at Home
As a rule, Action Chaining is not recommended. First explore other options, such as the Redirect After Post technique.
Take a look at this answer too: https://stackoverflow.com/a/4761955/1654265