Useful technical links - MAPI

[norman]

If using Exchange Server then you should consult the available logs. Outlook cannot connect to the Exchange Server by using MAPI over HTTP when a proxy is enabled that has your own domain listed as an exception.

Microsoft Exchange: Test MAPI connectivity of user mailbox
https://social.technet.microsoft.com/wiki/contents/articles/22773.microsoft-exchange-how-to-test-the-mapi-connectivity-of-user-mail-box.aspx

MAPI solutions do not work because Outlook.exe is not properly registered under the \App Paths key in the Registry
https://support.microsoft.com/en-ca/help/2698523/mapi-solutions-do-not-work-because-outlook-exe-is-not-properly-registe

How to allow MAPI to load unregistered Provider DLLs
https://support.microsoft.com/en-hk/help/4498413/how-to-enable-mapi-to-load-unregistered-provider-dlls

Outlook 2010, 2013, 2016, or Outlook for Office 365 may not connect using MAPI over HTTPs as expected
https://support.microsoft.com/en-us/help/2937684/outlook-may-not-connect-using-mapi-over-https-as-expected

How to configure Outlook as your MAPI provider
https://support.exclaimer.com/hc/en-gb/articles/360004503072-How-to-configure-Outlook-as-your-MAPI-provider

How to allow MAPI to load unregistered Provider DLLs
https://support.microsoft.com/en-hk/help/4498413/how-to-enable-mapi-to-load-unregistered-provider-dlls

While not our program this indicates an issue in Outlook -
Error: "This MAPI provider DLL might be harmful to your system" When Sending Emails in Outlook Versions 2016 & 2019 with Kerio Connect Version 9.2.9
https://support.gfi.com/hc/en-us/articles/360008700140-Error-This-MAPI-provider-DLL-might-be-harmful-to-your-system-When-Sending-Emails-in-Outlook-Versions-2016-2019-with-Kerio-Connect-Version-9-2-9

Unable to send MAPI Email with 64 bit Microsoft Outlook
https://help.acctivate.com/articles/5315/