Recipient Limits per Email Sent

Yes, in order to help protect against spam and mail flooding attacks, No-IP limits the number of recipients per email to 50. They can be either in the To:, CC:, or BCC: address lines, but there’s a maximum of 50 allowed. If you need to send the same message to more than 50 addresses, you’ll have to break the message up in groups of 50 in order to send it.

Don’t forget that each recipient counts towards your total mail allowance, so sending one message to 50 people is the same as sending 50 individual messages for the purposes of measuring usage.