I have installed Bitbucket server, when i browse ( http://localhost:7990) URL then showing below error.

[Nitin Sharma]

image2016-9-9 16:55:32.png

[Jeff Thomas]

There can be a few causes for the SSH plugin to timeout during start up. Please review "Required plugin com.atlassian.stash.ssh-plugin has failed to start" is displayed when accessing the Bitbucket Server web interface which provides a few causes and solutions. 

Most likely, there is not sufficient entropy on the server and /dev/random is hanging which causes the SSH plugin to fail to start. This is explained in more detail in the above link.