Have you ever been in a situation where you send an invitation to your colleague to be a part of the team, however, they don't receive it? There can be a couple of reasons behind this. First, ask your colleague to check their Spam folder. Maybe their email provider isn't allowing them to receive emails from Whatagraph. Another reason behind this could be a university email address. If after checking these, there's still no invite email, try sending the invitation again.