Outlook 2013 Error Code 0x8004210B - "550 5.5.3 Too many recipients"

Question 1: I have installed Office 2013 Standard but for some reason in the Add / Remove programs from the Control Panel I see Office 2013 Pro Plus installed. Does anyone perhaps know why?

Question 2: I have configured an IMAP e-mail and is always receiving the 0x8004210B error code. I have tried many things such as disabling the virus scanner, checking firewall, changed ports but unfortunately to no avail. This is an IMAP account and not POP so no .PST is created but an .OST as I have already searched online and found misleading info. I have configured the SMTP to use default port 110 and then tried port 587 but to no avail. I have also changed the server timeouts value to a max of 5 minutes. Any help on this please?

"The full error code message is 'Sending reported error (0x8004210B): 'The operation timed out waiting for a response from the sending (SMTP) server. If you continue to receive this message, contact your server administrator or Internet Service Provider (ISP). The server responded: 550 5.5.3 Too many recipients."
 
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