Seems that Swisscom/bluewin's mail servers are blocking each other again, same problem happened on February 14.

Generierender Server: #< #5.0.0 smtp; 554 IP:, You are not allowed to send us mail. Please see if you feel this is in error.> #SMTP#

Last time zhhdzmsp-smtp12 was even blacklisted for SPAM.

Anyone else get the same problem?