BCC quit working today 5/17/19
Apple Mail BCC quit working suddenly today on Mail V. 11.5. It causes a server error on ATT/Yahoo mail.
I reset server, reinstalled mail account, and still get the message
"Cannot send message using the server selected ----) I can send list mail in CC and To lists but not to BCC lists.
I use BCC for list mailings to keep recipients mail addresses private.
Any ideas?? ATT support was totally useless.
iMac 27", macOS 10.13