A social account can only be connected to one Haiilo account at a time. If you receive an error when connecting your social account saying that it's already connected to another Haiilo account, you need to find out where your account is connected and disconnect it from there.
If you had a previous account with Haiilo under a different company or had a test account within your current domain, and your social account was linked to it, you must disconnect the social connection from the other account or delete it.