I am using CMapi to send a bulk email using MFC. In my To string, I use a semi-colon to separate addresses and this has been working fine. However, I have recently added two new email addresses in my list, which for some reason prevent ANY of the recipients from receiving the email if they were included in the same string.
I have done some investigation into the possible reasons for this, and have so far deduced the following. If I send the same bulk email manually using Outlook, there is no problem. Also, when I run the same program from another site there is no issue (which leads me to believe it may be something to do with the outgoing mail server). I can send emails to other addresses with the same domain name, so the domain is not a problem. Neither are there any characters used in either of these emails which are in others that do work.
I do know that both of these problem-email addresses have mail forwarded to them from other (older) addresses if that helps. When I use their old addresses, it doesn’t work either.
Any suggestions would be greatly appreciated.