The Request new project and Create project from a template are not working and observe a blank pop up window. As a result, the JIRA instance goes down.
Root cause: Two project templates have a reciprocating parent template. Meaning, Project Template A is a Parent Template of Project Template B, and Project Template B is a Parent Template of Project Template A. As a result, "The Request new project" and "Create project from a template" show a blank pop up window. And also if a new project template is created and the two templates having reciprocating parent templates are disabled, then also a blank pop up window appears.