Problem & Symptoms
If you install WProofreader directly on the server with Apache Tomcat, and your application and WProofreader are located in different domains, for example, webspellchecker.com and webspellchecker.net, a CORS issue may occur. To solve this issue, add the Access-Control-Allow-Headers to enable cross-control requests to the Apache Tomcat settings.
Solution
To solve this issue, add the Access-Control-Allow-Headers to enable cross-control requests to the Apache Tomcat settings.
Refer to Option A: Binding of Static Files and Serving Service Requests by AppServer for details.