Overview
Sending out large quantities of email is restricted to help prevent compromised accounts from spreading phishing and other malicious emails to other university accounts. This article summarizes the limits different accounts can send within a one hour and within 24 hours. Once a limit is reached the sender will not be able to send emails until the next day. See related articles for approved methods to send bulk or mass emails.
When an account hits the sending limit they will see a bounce message that includes:
550 5.1.8 Access denied, bad outbound sender
For additional information on the error: https://support.uidaho.edu/TDClient/40/Portal/KB/ArticleDet?ID=2233
| Policy/Group Name |
External Recipients Per Hour |
Internal Recipients Per Hour |
Total Recipients Per 24 Hours |
Auto-Forward |
| Certain Accounts Deemed High Risk |
50 |
50 |
100 |
Yes |
| Bulk or Mass Emails |
10,000 |
10,000 |
10,000 |
No |
| Employees |
500 |
500 |
1,000 |
No |
| Students |
250 |
250 |
500 |
Yes |
Warning: In addition to these limits, each account has a limit of 500 recipients per message.
It is recommended to use a functional account for an exception to the sending limit but there is a potential issue with SendAs permissions.
- Warning: When using SendAs permissions and just changing the From: address, the signed in user restriction will be used.
To work around this limitation here are some options:
- Use Outlook for the Web to access the functional mailbox at https://outlook.office.com/mail/functional-username@uidaho.edu.
- This will properly use the functional account sending restrictions for outbound messages.
- This is the recommended method for sending from a functional or shared mailbox.
- Create a dedicated Outlook profile for the functional account which is separate from your personal account.
Warning: It is also possible to SendAs a mail-enabled security group. In these cases the *default* 500 recipient limit is always used and cannot be increased. The only method to resolve this limit is to SendAs a functional account mentioned above.