Cannot send Outlook mail with 'Send Outlook Mail Message' or 'send mail' activity if the Outlook desktop app is not open.
The Send Outlook Mail Message Activity is designed to work even if the Outlook desktop app is not launched - it must be installed on the computer, however.
However, it can happen that Outlook profile/ application takes longer time to load in the background due to add-ins, multiple profiles configured, etc. In such cases,
- Use the Start Process activity to launch the Outlook application before using the Outlook activities like Get\Move\Send Outlook Mail Message.