The original message was received at Mon, 20 Nov 2023 17:12:35 -0500 from m0338032.ppops.net [127.0.0.1] ----- The following addresses had permanent fatal errors ----- <Sultan_Orazbayev@hks.harvard.edu> (reason: 554 5.4.14 Hop count exceeded - possible mail loop ATTR34 [SA2PEPF00001504.namprd04.prod.outlook.com 2023-11-20T22:12:36.524Z 08DBE7529D5E22D3]) ----- Transcript of session follows ----- ... while talking to hu.mail.protection.outlook.com.:

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DATA <<< 554 5.4.14 Hop count exceeded - possible mail loop ATTR34 [SA2PEPF00001504.namprd04.prod.outlook.com 2023-11-20T22:12:36.524Z 08DBE7529D5E22D3] 554 5.0.0 Service unavailable