This issue has been placed here some times (https://answers.atlassian.com/questions/281156 and Getting "An error occurred while trying to contact JIRA"), and I know a work-around for it, but I want need a proper solution for the issue.
We're using JIRA version 6.4.1.
Issue:
The error message "An error occurred while trying to contact JIRA" is shown when I want to create a new project.
Workaround:
Go to a page where you need to provide your admin's password again (for example: user management). Once you've confirmed your password, you can use the Create project link.
What can we do to resolve this issue permanently?