Hallo,

ich kann seit Kurzem keine Mails von t-online.de an eine hotmail Adresse schicken. 

Weiß jemand, woran das liegt?

Hier die Fehlermeldung:

....@hotmail.de>: host eur.olc.protection.outlook.com[52.101.68.33] said: 550 5.7.515 Access denied, sending domain T-ONLINE.DE doesn't meet the required authentication level. The sender's domain in the 5322.From address doesn't meet the authentication requirements defined for the sender. To learn how to fix this see: https://go.microsoft.com/fwlink/p/?linkid=2319303 Spf= Pass , Dkim= Fail , DMARC= Pass [VI2PR03MB10907.eurprd03.prod.outlook.com 2025-06-20T05:02:14.917Z 08DDAECF294D5349] [DUZPR01CA0148.eurprd01.prod.exchangelabs.com 2025-06-20T05:02:15.353Z 08DDAF66C28D7A45] [DU6PEPF0000B61C.eurprd02.prod.outlook.com 2025-06-20T05:02:14.943Z 08DDAEF632385233] (in reply to end of DATA command)