Unable to delete in Collab Workspace

I’m trying to delete whatever I accidentally imported as reference. However, I am unable to do so and it’s giving me this error. i have already tried changing the maturity state and ensured I’m the owner and current project is selected but nothing I try works for now. 

This was exported using global export in the batch utility from a different license (but same 3DX account), and imported as reference. 

Edu ​​​​​​​Eduspace