server-side sync for CRM on-premise 2016 with exchange server (online)

Hi all, 

I am facing this problem when I am configuring my mailboxes with server-side sync 

I am using exchange online and my CRM is on-premise. I followed all the steps needed for the configurations, but when it comes to testing and enabling the mailboxes, it is set to "Not Run". and on the top " The email configuration test is scheduled" but I never received the test email. 
Plus, no alerts appeared since 30-11-2016, even though I tried the test this after that date.