Invitations are sent by administrators to specific users from the Control Panel. Activation Emails are sent by our system after a client has signed up to a community. Both of these accomplish the same goal: they ensure the user has a valid email address our system can mail to.

Unfortunately, sometimes these emails do not go through. There are a number of possible causes for this but, currently, our system does not inform administrators when this happens.

- The email address is invalid: this is when there is a typo in the address or the address is no longer being used.

- Our emails are sometimes blocked by the recipient's email servers. - Some email servers use a whitelist system. They will only receive emails from servers they trust. If this is the case Igloo will need to be whitelisted before any of our emails can be received.

- Filtered to Junkmail: Sometimes spam filters send our emails to the Junkmail folder where they may be ignored by the recipient.