The ResourceConfig instance does not contain any root resource classes

my jira server just log this error constantly, I don’t know how to fix it. Though it may not affect anythings,but cause the log file really heavy.

http://host/plugins/servlet/project-config/NEWPRODUCT/fields
another problem is : I canot open this fields schema in project-config,but I can open other schema in project,it return 504 Gateway timn-out, and I cannogt find any error log in my server