I'm unable to create content fragment model in one of our environments even when i'm logged in with admin. It throws server error.
Attaching screenshot and stack trace in the comments below.

22.05.2020 04:23:03.064 *ERROR* [10.30.60.206 [1590139383053] POST /mnt/overlay/dam/cfm/models/console/content/createmodelwizard.html/conf/dam/cfm/models/console/content/createmodelwizard/_jcr_content HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Uncaught SlingException
java.lang.NullPointerException: null
at org.apache.jsp.apps.cq.Page.POST_jsp._jspService(POST_jsp.java:208)
at org.apache.sling.scripting.jsp.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) [org.apache.sling.scripting.jsp:2.3.6]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725) [org.apache.felix.http.servlet-api:1.1.2]
at org.apache.sling.scripting.jsp.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:502) [org.apache.sling.scripting.jsp:2.3.6]
at org.apache.sling.scripting.jsp.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:449) [org.apache.sling.scripting.jsp:2.3.6]
at org.apache.sling.scripting.jsp.JspScriptEngineFactory.callJsp(JspScriptEngineFactory.java:339) [org.apache.sling.scripting.jsp:2.3.6]