Here is the root of your problem - your organization was in Exchange ecosystem before switching to G Suite That is not his problem. That is google's problem. I

Here is the root of your problem - your organization was in Exchange ecosystem before switching to G Suite That is not his problem. That is google's problem. Ironically, thinking that this is the user's problem may be the root of google lagging in this area. Microsoft Exchange is deeply entrenched in the corporate world. When you send an invite to a client (or vice versa) and it fails due to integration issues, the typical client will be thinking "oh this is weird; I don't have issues with accepting or sending invites to anyone else!". You don't want to be that guy in your client's head.