When you as a Team Owner or Team Admin invite a new user to your team, the new user is sent an email with a signup link. Following that link ensures that their signup identity is connected to your team.
Some aggressive spam filters block these emails because they perceive a link in an email from a new sender to be a high risk of phishing. As a result, your invited user will not receive the email.
The fastest resolution is to share directly to them (via messaging or your email) the unnique signup link which you will find in the email that you received when you add them to your team.
We also recommend suggesting to a user that they add Ovida to their contacts list.