I am getting the error msg: 
Task *** Email address is removed for privacy *** - Sending' reported error (0x800CCC67) : '  The server responded: 421 #4.4.5 Too many connections from your host.'

This is appearing on all four of my email addresses and on two separate computers, both connected to the same broadband modem.

Is this an Outlook problem or an NBN provider issue?

I have also tried to send an email from my mobile phone and got the msg: webmail.au.syrahost.com is not available.  Is this also relevant?

Any assistance is very much appreciated.