ownership issues

Hello

I am the new owner of a workspace containing several folders. One of my colleagues who has no paid account is experiencing issues. He was admin of the workspace before and is still admin now.He is listed as owner of some files but they are now read only to him -he gets the message of needing a paid plan. They also are read only to me. I cannot transfer the ownership as 'the current owner is not recognized as part of my organization'. Any idea of why we are having this issue and how to solve it?

Thanks

Answers