Calling

OUTLOOK_LIST_MESSAGES

consistently returns a 503 error from Microsoft Graph. The error occurs both with a custom OAuth app registration and with Composio's managed OAuth configuration. Only a small number of manual calls have been made over the past several hours with no other processes running. Two distinct 503 messages have been observed: "Application Request Queue Full" and "Authentication Concurrency Limit Reached".

Hi there, Sorry for the trouble with this. Those two messages ("Application Request Queue Full" and "Authentication Concurrency Limit Reached") come back from Microsoft Graph / Entra, but the usual "you're being rate limited, slow down" explanation doesn't square with what you're seeing: only a few manual calls, and the same errors on both your custom OAuth app and our managed OAuth. We've seen this pattern reported and are tracking it internally, so we'd like to correlate your calls against our logs rather than guess. Could you share: • The request IDs and UTC timestamps for 2-3 of the failed

OUTLOOK_LIST_MESSAGES

calls • The

connected_account_id

you're calling with (one for the managed, one for the custom app if you have both) With those we can pull the exact upstream responses on our side and see whether this is a token-acquisition concurrency issue or a genuine Graph-side throttle. Just reply here with those and we'll dig in. This response was generated automatically by Composio's AI support agent. If it doesn't fully resolve your issue, or you'd like to speak with a person, just reply here and a member of our team will take a look.