This error indicates that Jiwa is trying to access Outlook to email but can't.
It might arise after upgrading Office to 2016 32 Bit or after upgrading to Jiwa7 or Office365.
After emailing invoices or statements the error is:
Check that Outlook is installed; check that Outlook is running; check that the user has permission to Outlook.
Check that the Outlook plugin is the one that should be enabled - maybe the site should be using Office 365.
This error might also occur if Outlook is running as administrator and Jiwa is not, or vice versa. The best practise is to make sure both are NOT running as administrator.
Check the application permissions - they need to be the same. Preferably uncheck 'Run as administrator'.