[StAPF] Undeliverable mail: Resolution zu Verwaltungsgebühren an Hochschulen

Failed to deliver to &#39;president(a)uni-kl.de&#39; SMTP module(domain exchange.uni-kl.de:25) reports: message text rejected by exchange.uni-kl.de:25: 554 5.4.12 SMTP; Hop count exceeded - possible mail loop detected on message id <5ebd250a-caa5-4fe3-9854-723c0b97914f(a)zapf.in&gt;