Do CCs and BCCs count against my daily SMTP Relay limit?
Yes. Addresses listed in the CC and BCC fields count against your daily SMTP Relay limit. One relay consists of an email message sent to one address using the SMTP service. So, if you send one email message to 30 addresses, it counts as 30 relays.
Relays are counted on a daily basis and your daily allotment is reset each night between 10 P.M. and 4:00 A.M., Arizona time.
With Workspace Webmail and SMTP, you are restricted to 100 email addresses (To, Cc, and Bcc) per email message, regardless of the number of SMTP relays you have per day. For more information, see Email Account Limitations.