Classic Outlook event-based add-in: fetch/XMLHttpRequest fails in JavaScript-only runtime

Hi scomesana_v, event-based add-ins in classic Outlook have a tighter JavaScript runtime than a normal task pane, so network calls can fail because of runtime limits, CORS, manifest domains, or timing. Confirm the endpoint is HTTPS, listed correctly in the manifest where required, and returns proper CORS headers. I would also log whether the request fails before sending, after preflight, or on response handling. That tells you if this is a policy/runtime issue or a server-side response issue.