ItemSend Event for Appointment Outlook Addin throwing manifest validation error - outlook

Question

I'm trying to have an on send handler assigned to a function within an Outlook addin for an Appointment. I strictly follow the manual, but I'm getting an error on the manifest validation
Error #1:
Mailbox add-in containing ItemSend event is invalid.: Mailbox add-in containing ItemSend event is invalid.
- Details: Mailbox add-in manifest contains ItemSend event in VersionOverrides which is not allowed.
My manifest.xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<OfficeApp xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides/1.0"
xsi:type="MailApp">
<Id>90992a37-6ac0-4e31-8f4d-c35d61ac033b</Id>
<Version>1.0.0.0</Version>
<ProviderName>CKT (dev)</ProviderName>
<DefaultLocale>en-US</DefaultLocale>
<DisplayName DefaultValue="Sync events with CKT Portal (dev)"/>
<Description DefaultValue="Sync events of Outlook with CKT portal (dev)"/>
<IconUrl DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/ckt.gif"/>
<HighResolutionIconUrl DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/ckt-128x128.gif"/>
<SupportUrl DefaultValue="https://ckt-d.internal.epo.org"/>
<AppDomains>
<AppDomain>https://ckt-d.internal.epo.org</AppDomain>
</AppDomains>
<Hosts>
<Host Name="Mailbox"/>
</Hosts>
<Requirements>
<Sets>
<Set Name="Mailbox" MinVersion="1.8"/>
</Sets>
</Requirements>
<FormSettings>
<Form xsi:type="ItemRead">
<DesktopSettings>
<SourceLocation DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/taskpane.html"/>
<RequestedHeight>250</RequestedHeight>
</DesktopSettings>
</Form>
</FormSettings>
<Permissions>ReadWriteMailbox</Permissions>
<Rule xsi:type="RuleCollection" Mode="Or">
<Rule xsi:type="ItemIs" ItemType="Appointment" FormType="Edit" />
<Rule xsi:type="ItemIs" ItemType="Appointment" FormType="Read" />
</Rule>
<DisableEntityHighlighting>false</DisableEntityHighlighting>
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
<Requirements>
<bt:Sets DefaultMinVersion="1.8">
<bt:Set Name="Mailbox"/>
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<FunctionFile resid="Taskpane.Url"/>
<ExtensionPoint xsi:type="AppointmentOrganizerCommandSurface">
<OfficeTab id="TabDefault">
<Group id="apptComposeDemoGroup">
<Label resid="groupLabel" />
<!-- Task pane button -->
<Control xsi:type="Button" id="TaskpaneButton">
<Label resid="TaskpaneButton.Label" />
<Supertip>
<Title resid="TaskpaneButton.Label" />
<Description resid="TaskpaneButton.Tooltip" />
</Supertip>
<Icon>
<bt:Image size="16" resid="Icon.16x16" />
<bt:Image size="32" resid="Icon.32x32" />
<bt:Image size="80" resid="Icon.80x80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="Taskpane.Url" />
</Action>
</Control>
</Group>
</OfficeTab>
</ExtensionPoint>
<ExtensionPoint xsi:type="AppointmentAttendeeCommandSurface">
<OfficeTab id="TabDefault">
<Group id="apptReadDemoGroup">
<Label resid="groupLabel" />
<!-- Task pane button -->
<Control xsi:type="Button" id="TaskpaneButton2">
<Label resid="TaskpaneButton2.Label" />
<Supertip>
<Title resid="TaskpaneButton2.Label" />
<Description resid="TaskpaneButton2.Tooltip" />
</Supertip>
<Icon>
<bt:Image size="16" resid="Icon.16x16" />
<bt:Image size="32" resid="Icon.32x32" />
<bt:Image size="80" resid="Icon.80x80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="Taskpane.Url" />
</Action>
</Control>
</Group>
</OfficeTab>
</ExtensionPoint>
<ExtensionPoint xsi:type="Events">
<Event Type="ItemSend" FunctionExecution="synchronous" FunctionName="validateBody" />
</ExtensionPoint>
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
<bt:Images>
<bt:Image id="Icon.16x16" DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/ckt.gif"/>
<bt:Image id="Icon.32x32" DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/ckt-32x32.gif"/>
<bt:Image id="Icon.80x80" DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/ckt-80x80.gif"/>
</bt:Images>
<bt:Urls>
<bt:Url id="Taskpane.Url" DefaultValue="https://ckt-d.internal.epo.org/addins/outlook/taskpane.html"/>
</bt:Urls>
<bt:ShortStrings>
<bt:String id="groupLabel" DefaultValue="CKT Add-in (dev)"/>
<bt:String id="TaskpaneButton.Label" DefaultValue="CKT (dev)"/>
<bt:String id="TaskpaneButton2.Label" DefaultValue="CKT (dev)"/>
</bt:ShortStrings>
<bt:LongStrings>
<bt:String id="TaskpaneButton.Tooltip" DefaultValue="Sync Outllook events with CKT as Organizer (dev)"/>
<bt:String id="TaskpaneButton2.Tooltip" DefaultValue="Sync Outllook events with CKT as Attendee (dev)"/>
</bt:LongStrings>
</Resources>
</VersionOverrides>
</VersionOverrides>
</OfficeApp>
What am I missing?

Answer 1

Our documentation is updated regarding office store validation with
office-addin-manifest script. Please check here:
https://learn.microsoft.com/en-us/office/dev/add-ins/testing/troubleshoot-manifest#validate-your-manifest-with-office-addin-manifest
Add-ins with On-Send events are not allowed on the add-in store. They can only be installed by the organization admin or manually.