The development team is complaining that when they try to select a metadata source in...

Set the Copado DX Mode picklist field in the Pipeline record to 'None'.

Set the Copado DX Mode picklist field in the Pipeline record to 'All Metadata Sources'.

Give the developer profile the correct object level permissions to all metadata sources.

Set the Copado DX Mode picklist field to 'Branches' in all the environments.