Thanks for reaching out to the Microsoft Q&A forum.
To help me better understand your situation, may I clarify some points?
First, when you mention that the add‑in does not integrate with Outlook, could you share whether you are unable to add it to Outlook at all, or if you can add it but it stops working afterward?
Additionally, please verify whether the web add‑ins have been added in the classic Outlook desktop app, please follow this path: File > Info > Manage Add‑ins
This will open the Add‑ins page in Outlook on the web. Once there, please confirm whether the add‑in appears under My add‑ins.
If it does, you may try removing it and then adding it again to refresh the setup.
Based on my personal experience, after an add‑in is enabled in Outlook on the web, the classic Outlook desktop application may take some time to synchronize these changes. In certain cases, this process can take up to 24 hours. Because of this, it is important to make sure the add‑in continues functioning properly in Outlook on the web during this period.
If you encounter any error messages when adding the add‑in or while using it, please feel free to share them with me through the private message.
Please check your inbox for an email with the subject “New private message on Microsoft Q&A question” to review my response.
If I’ve misunderstood any part of your situation, or if you have further questions or updates, please don’t hesitate to reply.
Thank you for your time, and I look forward to hearing from you soon.
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