Using Creator I created an application called Questionario.
I added 233 users authorized to use the application : many users  have regularly received an email invitation , while the last few 40/50 did not receive the invitation email .
I tried to select a few names among the unconfirmed user and select reinvite , but the email still does not arrive.
This is my Plan Details
Current Plan : Professional Express
Total Users : Unlimited
Active Users : 233
What could be the problem ?