There are several possible causes for this failure:
1. Review whether your using a SMTP gateway. If you configured a SMTP gateway for your mailserver, please unsure that this system is correctly configured and working.
2. Review whether your internet connection is available and you can manually connect to the destination SMTP server.

Most of the times this error occurs because the mailserver cannot access the destination SMTP server due to network errors.

Go to the menu Services -> Webserver -> Configuration to verify if a file share has been defined for the webmail to run from. Select a share and try to activate the webmail service again.

Because of security reasons, the incoming emails on the server are being thoroughly scanned before they are delivered to the network user. At this stage the mails are in a sort of waiting room before they are being scanned. Every 3 minutes all the mails in the waiting room are being scanned and delivered to the user if they are virus free. If they contain viruses the sender of the message is being notified.

There is no uniform way to give someone access to your personal email. There are some workarounds which can be enabled to give someone temporary access to your email. Suppose Bob wants to give Alice temporary access to his email, the administrator can allow this by:

1. Add the user Alice to Bob's email address through the GUI. This will allow Alice to receive all email for Bob.
2. Temporarily reset Bob's password and configure Alice's mailbox to check both her and Bob's mailbox. Don't forget to reset the password once Bob returns.