Not being able to invite team members

Hello, I am building a Flutter Application and I am using AppWrite self-host as my backend solution. Just to be clear the issue that I'm about to describe is not happening on local, is on a live server. I've created a project in which I've invited at the starting point besides me one of my colleagues(using the member invite functionality from the console). Everything went smooth and we both received the invitation. A few days ago I had to add a new member but the invitation is not sending. I get that pop-up saying that "Invitation has been sent to ..." and nothing on the e-mail. I've also performed some tests and invited myself on my personal account and I've encountered a weird behaviour. Sometimes I receive the email, sometimes I don't. But for the other team member he did not receive it at all. Is there a configuration that needs to be done? Why sometimes I get the invitations and sometimes not(2 out of 4/5 tries I got it) and why my team mate did not get it at all. To mention he is not using a conventional gmail account he has a business one. Thanks for the help!