Yahoo Mail email sending limits
To help prevent spam and potential abuse, Yahoo has limits on how many emails can be sent at a given time from a Yahoo Mail account, as well as how many recipients an email can be sent to at once.
What are the limits?
We don't disclose the specific limits on the number of emails you can send, or the number of contacts you can email at once. We have these limits in place to reduce spam and misuse of Yahoo Mail.
What if you've reached the limit?
Were you notified that you reached the hourly or daily sending limit? Please allow the appropriate amount of time to pass (e.g., an hour or day) before trying to send again.