Auto Email Sender4 Common Reasons and Solutions for Failure to Send Emails
There is a small list of 4 common reasons for failure to send emails below, and you can find the solution for each issue.
Error Code List and Solutions
550 Invalid User: The user is invalid and the email address cannot be found. Some mailboxes think that you are sending a spam mailbox and also return this message.
Solution: Check and modify the email content and try again. If it still doesn't work, delete the invalid email address.
550 User is locked: the SMTP client function is not activated.
Solution: The mailbox provider generally provides an activation method, search online or contact the mailbox provider to activate.
4.x.2 Too many messages for this session: Send too many messages at once.
Solution: Use the sending strategy and reduce the sending speed.
5.4.5 Daily sending quota exceeded: The sending limit of today is exceeded.
Solution: Send after 24 hours.
Didn't find the error code of your email delivery failure? For more information, please read 14 Reasons and Solutions for Email Delivery Failure and Return Messages.
Auto Email Sender is a free bulk email sending tool that sends emails in batches to multiple user email boxes, supports HTML format and attachment addition. Click here to check more details.
Download Auto Email Sender Now!
Windows XP / Vista / Windows 7 / Windows 8 / Windows 10 / Windows 11 & Server (64/32 bit) - 0.9 MB
Portable Version (60 KB, ZIP Format)
Windows XP / Vista / Windows 7 / Windows 8 / Windows 10 / Windows 11 & Server (64/32 bit) - 0.9 MB
Portable Version (60 KB, ZIP Format)