What does the International No Symbol mean next to a sent message in Mail?

Hello The_Hawk,

So you're seeing a circle with slash icon on the sent messages. Thanks for clarifying!

That typically indicates that you have yourself (your own email address) added to your blocked list. Go into one of the sent emails then at the top, right click on your name and select Unblock Contact. Then check your sent folder to see if the circle with slash icons have disappeared.

Cheers!

Hey there The_Hawk,

The symbol being seen could have a couple different meanings. The information below might be helpful for your client:

"You might see a status icon such as a lightning bolt  or a warning icon  next to your account's inbox in the Mail sidebar, or in the upper-right corner of the Mail window. Click it to learn more.

• If the status is Network Offline, make sure that your Mac is connected to the internet, then try again.
• If the status is Login Failed, check with your email service provider (ESP) to be sure that your account is set up correctly on your Mac.
• If Mail asks for your password, but entering the password doesn't help, find out why your email provider is rejecting your password.
• If your email service is experiencing a temporary outage, your email provider might have a status message on their website. For example, Apple's system status page shows the status of iCloud Mail. Status pages are also available for other email services, such as Gmail and Outlook. Some brief service outages might not appear on a system status page, so you might want to wait a few hours and try again."

They might want to reach out to the email service provider as well if there are any issues with sent emails.

Take care!

Those indicate a blocked contact. You should also see a header over the body text that says something along the lines of "this message is from a blocked sender."