[Druid] Undelivered Mail Returned to Sender

This is the Email Security Gateway at host mailstub2.santannapisa.it. I'm sorry to inform you that the message below could not be delivered. When delivery was attempted, the following error was returned. <edoardo.ferrucci@santannapisa.it>: host santannapisa-it.mail.protection.outlook.com[52.101.73.4] said: 554 5.4.14 Hop count exceeded - possible mail loop ATTR34 [AM4PEPF00025F99.EURPRD83.prod.outlook.com 2024-02-18T15:51:05.640Z 08DC2F13D5D3560A] (in reply to end of DATA command)