'DOCTYPE is disallowed' Error when using Enrich Button

Problem

When clicking on the enrichment button the following error message is shown "Error when calling service:'Error 'DOCTYPE is disallowed when the feature "http://apache.org/xml/features/disallow-doctype-decl" set to true.' during processing of the response.'."

Solution

The most common reasons for this error message are:

• Wrong URL address in the validators.xml from your model project configuration files (configurationFiles.zip). In most cases, the URL is pointing to the RDM web application instead of the Admin Center. In order to fix this, you will need to define the correct server connection which points to the Admin Center within your IDE and use it for the enrichment. Afterward, make sure that you save your model project and reload metadata. Once you are done you can generate the configuration files and deploy them in the RDM admin console.
• Not passed credentials in validators.xml for the Admin Center. In case that the Admin Center is secured and requires credentials in order to log in,  you will need to check if credentials are added for the server in the server node from the IDE. Once you are done, generate and deploy the configuration files.
• Direct Access Grants have not been applied on the side of Keycloak or basic authentication has not been enabled in the client configuration. You would need to verify the following settings in order to troubleshoot the issue. 
  1. If you have Direct Access Grants enabled for the following clients in Keycloak: one-rdm-steps and one-admin-center
  2. If there is identityProvider node in securityFilter in serverConfig.xml. If so, you will need to edit the runtimeConfig or JSON file (depending on your configuration) and add enable-basic-auth.
  3. If identityProvider for RDM is missing you will need to check the settings for the Admin Center and enable-basic-auth in the same way as described above for the RDM.