A lot of Mac users faced this issue when sending an email in the Mail app on Mac. This problem will occur if the SMTP server is messed with the wrong accounts to use different servers. It’s really made frustrating. But don’t worry about this. Here I will show you how to fix this issue with simple solutions. Ok, let’s get started.

Solution 1: Edit SMTP Server list

  • Open Mail app.
  • Select Preferences.
  • In the Accounts tab, choose the account which is Outgoing Mail Server (SMTP) labeled as Offline.
  • Click the SMTP server and choose Edit SMTP Server List from the list.
  • Enter the right username and password.

Solution 2: Delete and Add SMTP

  • Quit Mail app.
  • Go to Applications > Utilities > Keychain Access and delete all SMTP passwords from the keychain.
  • Enter the name of your SMTP server in keychain search boxes like  mail.mailserver.com or smtp.mailserver.com.
  • Search and find the entry which starts with SMTP://. Copy and store the password in your hard drive in the different locations (for safety).
  • Delete all relevant password entries for SMTP servers.
  • Open Mail app and go to Preferences -> Accounts tab.
  • Choose your account SMTP server from the Edit SMTP servers list.
  • Re-enter the password that you just deleted.

Solution 3: Force Quit your Mac 

  • Go to Apple menu -> Force Quit.
  • Choose Mail app and select Force Quit.
  • Restart your computer.
  • Open the Mail app and check your issue.

Solution 4: Try DNS Address

Go to Network Preferences -> Advanced section of Ethernet and WiFi interfaces. Add the following DNS addresses.

Table of Contents

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Solution 5: Use Mail Preferences 

  • Go to Mail Preferences.
  • From the left side list, select the account which causes the issue.
  • Choose “Edit SMTP Server List” from the outgoing mail server drop-down menu.
  • Correct the username by appending domain name 9Ex: @gmail.com or your own domain).
  • Re-enter the password.

Solution 6: Quit your Mail App

  • Quickly press and release Option + Command + Esc key together.
  • From the Force Quit list select the Mail app.
  • Now give the Force Quit option.
  • After that reopen the Mail app and check if the problem is still occurring.

Conclusion

I hope this helps to fix this issue. If you know of any other solutions for the SMTP server offline Mac mail issue, kindly let me know through the comments section below. Thank you.