Dataflow refresh fail after ownership change

We are currently initiating a powerBI project in our orgnisation.

I'm the sysadmin of a sensitive database. Only me and the organisation power-bi gateway have permission to connect to.

So both of us have permission on the connection.

We created a workspace and gave acces to contributor in our team.

I created a dataflow and gave access to a contributor with legal right to view the data on it.

For him to modify the dataflow he took ownership.

Then, the next day the refresh failed with this error:

Error: Credentials not found for data source '<ccon>{"Kind":"PostgreSQL" "Path":"fakeservername

I thought the refresh failed because only me have right to the connection so i took ownership back.

But then the refresh continue to fail and i cannot set it up so it work again.

I tried to create a new dataflow to validate the connection is still working and it worked flawlessly.

So ... Why does this happen?, why can't I make the connection work when taking bak owner ship ?