Antwort:

The recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720 [mx01.t-online.de. 194.25.134.72: 421 IP=209.85.219.177 - No more parallel connections from your address allowed ] [mx02.t-online.de. 194.25.134.9: 421 IP=209.85.219.179 - No more parallel connections from your address allowed ] [mx03.t-online.de. 194.25.134.73: 421 IP=209.85.219.178 - No more parallel connections from your address allowed ] [mx00.t-online.de. 194.25.134.8: 421 IP=209.85.219.181 - No more parallel connections from your address allowed ]