550: Invalid Recipient error when replying to another Plusnet member

[#1]

Having problems replying to my sister lately who I previously referred to Plusnet. Currently she is on holiday in the UK but all her emails I reply to are bounced straight back with the following:

A message that you sent to the following recipient could not be delivered due to a permanent error. ** The remote server 212.159.8.200 responded with: ** xxxxxx@xxxxxx.plus.com 550:Invalid Recipient xxxxxx@xxxxxx.plus.com This message was created automatically by mail delivery software on the server avasout

[#2 · Accepted solution]

SOLVED!

This error occurs when replying to emails sent from Webmail when the user is sending from their default email account, i.e. joeblogs@joeblogs.plus.com

I got my sister to change her default email address to her regular one in the 'identities' section in webmail and now the problem has gone away.

Strange that webmail rejects emails sent to a Plusnet address though!