Issue: This message could not be sent. Try again later or contact your network administrator. Error [0x80004005-000000000-00000000]
Scenario: Organization has throttling policy with recipient rate limit of 10,000 per day set for the organization. For this org, service mailboxes aren’t throttled. User has 2 mailboxes (primary and service mailbox) opened in Outlook. User has send-as permissions to the service mailbox but as a group member.
User tries to send from outlook as service mailbox to multiple recipients but received error message. see error message below
Undeliverable: your message did not reach some or all of the intended recipients. This message could not be sent. Try sending message again later or contact your network administrator. Error is
Resolution: Advised user to send message using Outlook web Access. User needs to login to OWA and open the service mailbox. Messages can now be sent without throttling.
Alternatively, for a user that insist on using Outlook, user must be given explicit send-as permission to the service mailbox so as to be able to bypass throttling policy