The original message was received at Tue, 24 Oct 2023 07:48:19 -0400 from m0338036.ppops.net [127.0.0.1] ----- The following addresses had permanent fatal errors ----- <andres_gomez@hks.harvard.edu> (reason: 554 5.4.14 Hop count exceeded - possible mail loop ATTR34 [CY4PEPF0000EDD4.namprd03.prod.outlook.com 2023-10-24T11:48:20.447Z 08DBD24DAD6257D4]) ----- 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 [CY4PEPF0000EDD4.namprd03.prod.outlook.com 2023-10-24T11:48:20.447Z 08DBD24DAD6257D4] 554 5.0.0 Service unavailable