Since Content Services 6.2 the cm:content property cannot be set using the NodeService. Any code that uses NodeService methods setProperties, addProperties, createNode, addAspect, or setProperty to set the content property need to be refactored or designed to use the ContentWriter service instead. The ContentWriter can be obtained by using the ContentService. To use the ContentService, see ContentService.
There are ways to get around this security check: Add full class names as a comma separated list to a global property:
contentPropertyRestrictions.whitelist=org.alfresco.Class1,org.alfresco.Class2
Disable the ContentPropertyRestrictionInterceptor fully by setting a global property:
contentPropertyRestrictions.enabled=false
However, it’s better to refactor the code by using the ContentWriter.