Outlook WebAddin doesnt show up on Outlook Client

I have created an outlook web addin with visualstudio 2022 (I used the default template)
It works in the Outlook Web Client (OWA).
On an Outlook client with Office365 the addin is not displayed.
If I go to the addins under Installed web addins, I can see that the addin is active.

Could it be that there is an error in my manifest?

I would be grateful for any tips

<?xml version="1.0" encoding="UTF-8"?>
<!--Created:ce44715c-8c4e-446b-879c-ea9ebe0f09c8-->
<!-- Weitere Informationen zum XML-Manifest für Office-Add-Ins finden Sie unter https://go.microsoft.com/fwlink/?linkid=2252563. -->
<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">


  <!-- WICHTIG: Die ID muss eindeutig für Ihr Add-In sein. Wenn Sie dieses Manifest erneut verwenden, stellen Sie sicher, dass Sie diese ID in eine neue GUID ändern. -->
  <Id>cf933e3b-9987-4ef0-a079-a4b3defd66d0</Id>

  <Version>1.0.0.0</Version>
  <ProviderName>Spam Reporting</ProviderName>
  <DefaultLocale>de-CH</DefaultLocale>
  <!-- Der Anzeigename Ihres Add-Ins. Er wird im Store und an verschiedenen Stellen in der Office-Benutzeroberfläche verwendet, z. B. im Dialogfeld "Add-Ins". -->
  <DisplayName DefaultValue="Email Melden" />
  <Description DefaultValue="Email Melden"/>

  <IconUrl DefaultValue="https://reporting.test.ch/Images/icon32.png"/>
  <HighResolutionIconUrl DefaultValue="https://reporting.test.ch/Images/icon80.png"/>

  <SupportUrl DefaultValue="http://www.exchange.test.ch" />
  <!-- Domänen, die beim Navigieren zulässig sind. Wenn Sie z. B. "ShowTaskpane" verwenden und dann ein href-Link auftritt, ist die Navigation nur zulässig, wenn sich die Domäne in dieser Liste befindet. -->
  <AppDomains>
    <AppDomain>exchange.test.ch</AppDomain>
    <AppDomain>owa.test.ch</AppDomain>
  </AppDomains>
  
  <Hosts>
    <Host Name="Mailbox" />
  </Hosts>
  <Requirements>
    <Sets>
      <Set Name="Mailbox" MinVersion="1.1" />
    </Sets>
  </Requirements>
    
  <FormSettings>
    <Form xsi:type="ItemRead">
      <DesktopSettings>
        <SourceLocation DefaultValue="https://reporting.test.ch/MessageRead.html"/>
        <RequestedHeight>250</RequestedHeight>
      </DesktopSettings>
    </Form>
  </FormSettings>

  <Permissions>ReadWriteMailbox</Permissions>
  
  <Rule xsi:type="RuleCollection" Mode="Or">
    <Rule xsi:type="ItemIs" ItemType="Message" FormType="Read" />
  </Rule>

  <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="1.1">
          <bt:Set Name="Mailbox" />
        </bt:Sets>
      </Requirements>
      <Hosts>
        <Host xsi:type="MailHost">

          <DesktopFormFactor>
            <FunctionFile resid="functionFile" />

            <ExtensionPoint xsi:type="MessageReadCommandSurface">
              <OfficeTab id="TabDefault">
                <Group id="msgReadGroup">
                  <Label resid="groupLabel" />
                  <Control xsi:type="Button" id="msgReadOpenPaneButton">
                    <Label resid="taskPaneButtonLabel" />
                    <Supertip>
                      <Title resid="taskPaneButtonLabel" />
                      <Description resid="taskPaneButtonDescription" />
                    </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="messageReadTaskPaneUrl" />
                      
                    </Action>
                  </Control>
                  
                </Group>
              </OfficeTab>
            </ExtensionPoint>
          </DesktopFormFactor>
        </Host>
      </Hosts>

      <Resources>
        <bt:Images>
          <bt:Image id="icon16" DefaultValue="https://reporting.test.ch/Images/icon16.png"/>
          <bt:Image id="icon32" DefaultValue="https://reporting.talus.ch/Images/icon32.png"/>
          <bt:Image id="icon80" DefaultValue="https://reporting.test.ch/Images/icon80.png"/>
        </bt:Images>
        <bt:Urls>
          <bt:Url id="messageReadTaskPaneUrl" DefaultValue="https://reporting.test.ch/MessageRead.html"/>
        </bt:Urls>
        <bt:ShortStrings>
          <bt:String id="groupLabel" DefaultValue="My Add-in Group"/>        
          <bt:String id="taskPaneButtonLabel" DefaultValue="E-Mail melden"/>
        </bt:ShortStrings>
        <bt:LongStrings>
          <bt:String id="taskPaneButtonDescription" DefaultValue="Melden"/>
         
        </bt:LongStrings>
      </Resources>
    </VersionOverrides>
  </VersionOverrides>
</OfficeApp>