Redmine

I m running my redmine on remote sql server 2014. I can login successfully. But when i go to create a user and click the submit button. it shows the error:

*Internal error

An error occurred on the page you were trying to access.
If you continue to experience problems please contact your Redmine administrator for assistance.

If you are the Redmine administrator, check your log files for details about the error.*

I am not understanding how should I approach this problem.