The following nodes failed validation
This error occurs when a document edited by Fonto Editor has become invalid according to the schema.
Sometimes a document becomes invalid according to the schema that Fonto Editor works with. Whenever this happens the document no longer adheres to the same rules as Fonto Editor, and the user will no longer be able to edit it. If the operation which has triggered this error can be rolled back, it will and the user can continue working.
When this happens, consider the following possible causes:
The document that was loaded hasn't been updated together with the latest schema update.
The user might have loaded an old document into an existing map.
The document might not be encoded in UTF-8.
A certain construction may be configured as invalid, but was present, or has been created in a document.
Maintaining documents across schema versions is considered a responsibility of the CMS.
This error is followed by a jsonML representation of the nodes which have failed validation. Usually, the (absence of) attributes and/or the childNodes do not add up according to the schema.
Invalid documents are never saved.