Outlook加载项图标未显示

Question

出于某种原因，当我将清单文件加载到Outlook时，将显示我的Outlook加载项的默认图标。加载项在我们的组织内部托管 - 会导致此问题吗？

下面我选择了清单文件的相关部分。如果需要任何其他信息，请告诉我。任何帮助将不胜感激。

Manifest hosts：

<Hosts>
        <Host xsi:type="MailHost">
            <DesktopFormFactor>
                <ExtensionPoint xsi:type="AppointmentOrganizerCommandSurface">
                    <OfficeTab id="TabDefault">
                        <Group id="msgReadGroup">
                            <Label resid="groupLabel" />
                            <Control xsi:type="Button" id="msgReadOpenPaneButton">
                                <Label resid="paneAppointmentButtonLabel" />
                                <Supertip>
                                    <Title resid="paneCreateAptSuperTipTitle" />
                                    <Description resid="paneCreateAptTipDescription" />
                                </Supertip>
                                <Icon>
                                    <bt:Image size="16" resid="icon16" />
                                    <bt:Image size="32" resid="icon32" />
                                    <bt:Image size="80" resid="icon80" />
                                </Icon>
                                <Action xsi:type="ShowTaskpane">
                                    <SourceLocation resid="appointmentCreatePaneURL" />
                                </Action>
                            </Control>
                        </Group>
                    </OfficeTab>
                </ExtensionPoint>
            </DesktopFormFactor>
        </Host>
    </Hosts>

清单资源：

<Resources>
        ...
        <bt:Images>
            <bt:Image id="icon16" DefaultValue="https://intranet-domain.com/assets/icon-16.png" />
            <bt:Image id="icon32" DefaultValue="https://intranet-domain.com/assets/icon-32.png" />
            <bt:Image id="icon80" DefaultValue="https://intranet-domain.com/assets/icon-80.png" />
        </bt:Images>
        ...
</Resources>