When editing a Text Block in ComposerUI HTML5, a TinyMCE-based editor is loaded. For various reasons loading may fail. In this case, the following error message is prompted after a timeout.

 A timeout occurred while loading the editor. The application
		  failed to load the text block editor, or loading is slow. Please refer to the
		  JavaScript API Manual for ComposerUI for guidance on troubleshooting this
		  issue.

ComposerUI for HTML5 is integrated in a page of the customer's business application (for more information, see Introduction). This page should refer to a TinyMCE distribution (for more information, see Dependencies). This distribution contains KCM specific plug-ins. The latest version of this distribution is available on the server at:

https://<kcm server>/proxy/tinymce (or http://<kcm server>:8080/proxy/tinymce, if SSL is not enabled)

The version on the server always matches the KCM version. Furthermore, language packs are applied to this version.

If TinyMCE is consumed from another location, the following may cause problems when loading the Text Block editor:

• The TinyMCE distribution contains old versions of the plugins that do not match the KCM version on the server.
• ComposerUI is running with a custom language based on a language pack. This language pack is not applied on the TinyMCE distribution.

Either of these problems causes loading of the editor to fail and thus the timeout to occur.

In both cases, we strongly recommend that you refer to the TinyMCE distribution on the server. The example.html page that resides at the following locations contains more information about this subject:

https://<kcm server>/start/example/example.html (or http://<kcm server>:8080/start/example/example.html, if SSL is not enabled)