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Published Jun. 30, 2025

After upgrading, these ComboServlet errors are shown: 'Skip /o/js/resolved-module/... because its content type is not CSS or JavaScript'

Written By

Jose L. Bango

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Issue

  • Errors like the following appear in the server's log file after an upgrade: 
    ERROR [ComboServlet:389] Skip /o/js/resolved-module/frontend-js-tabs-support-web@2.0.12/TabsProvider.js because its content type is not CSS or JavaScript
    ERROR [ComboServlet:389] Skip /o/js/resolved-module/frontend-js-alert-support-web@2.0.10/index.js because its content type is not CSS or JavaScript
    ERROR [ComboServlet:389] Skip /o/js/resolved-module/frontend-js-dropdown-support-web@2.0.10/DropdownProvider.js because its content type is not CSS or JavaScript
    ERROR [ComboServlet:389] Skip /o/js/resolved-module/frontend-js-tooltip-support-web@4.0.17/index.js because its content type is not CSS or JavaScript
    ERROR [ComboServlet:389] Skip /o/js/resolved-module/frontend-js-collapse-support-web@2.0.13/CollapseProvider.js because its content type is not CSS or JavaScript

Environment

  • Liferay DXP Quarterly Releases

Resolution

  • These errors typically occur when the server attempts to find outdated versions of certain resources.
  • To tackle this issue, follow these steps:
    1. Stop the server.
    2. Clean the temporary folders of your installation:
      • [LIFERAY_HOME]/work
      • [LIFERAY_HOME]/osgi/state
      • [LIFERAY_HOME]/tomcat/temp (or equivalent)
      • [LIFERAY_HOME]/tomcat/work (or equivalent)
    3. Start the server again.
  • If the problem still occurs after cleaning the temporary directories, the files are likely to be cached. Double check your CDN or your browser's cache. In addition, double check if you have a customization that results in the wrong versions of .js files being served.
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