This error message has just started today. Be grateful if someone could tell me what it means and how to fix. Been getting odd messages in last couple of weeks re requests for passwords re my tiscali/lineone and o2 email addresses but I have clicked cancel and all has been well. Now this new message "An error occurred while sending mail: The mail server sent an incorrect greeting: mail.o2.co.uk Service not available - too busy" has arrived I can't send or receive emails. Be grateful for any help Thanks in advance..