If an add-in is embedded in a document and is not loading when opening the document, you need to check if the embedded add-in source is the same as the add-in available to you on your device. The add-ins can be added from different sources. They can be sideloaded, centralized deployed, or added via the Microsoft Store directly. As the Add-In source is part of the add-in embedding information, the embedded add-in in a document must originate from the same source as the add-in you have available. For example, if you deployed an officeatwork add-in through the Microsoft Store directly and embed it into a document, someone with the same add-in deployed via centralized deployment will not experience the add-in opening up together with the document.Related informationHow to automatically launch an Add-In alongside Word