This only works with Cloudlink chat enabled as NEPhoneGuy stated, with the "legacy" chat you cannot send or share files.
I ended up calling partner support, at first they agreed it was just CloudLink and turned it on. Still didn't work, actually the change they made broke MiCollab chat altogether. They then came back and indicated MiTeams is required. I understand CloudLink is required for MiTeams as well, but do we know if the statement that MiTeams is required for these Chat features in MiCollab to work? MiCollab and MiTeams are two different things. Sadly with MiTeams, the product is not HIPAA compliant yet so that's not an option yet.