Reference is not a dita resource

[NovaNowhere]

Every time i append a child and add a reference or add new it comes back as an error that its not a dita resource or the file is not found. WHy is this happening.

i am trying to add glossary.dita to my project, but this happens with any reference.

"Reference is not a DITA resource but is referenced as such."

[Radu]

Hi,

Could you give us some details about what version of Oxygen you are using?
Then some step by step details about what you are doing. Attaching a screenshot in which the error appears would also help us to know more about this situation.
If you open that "glossary.dita" in Oxygen is it reported as invalid in any way? What content do you have inside it?

Regards,
Radu