my outlook account will not send emails to multiple addresses using BCC.

Hi @Steve Cox

I understand why you need to keep members’ addresses private. BCC recipients still count toward Outlook’s sending limits, and messages sent to a large BCC list may be blocked by anti-spam protection.

Please try sending to a much smaller group and space the messages apart. Also check the exact error code in the undeliverable message, as it should indicate whether the cause is a sending limit, an invalid address, a full mailbox, or spam filtering.

For regular member mailings, Word mail merge or a dedicated mailing-list service may be more suitable because each recipient receives an individual message without seeing anyone else’s address,

Hope this helps. Have a nice day!