Fix the ‘message has lines too long for transport’ error in Outlook
Definitions
The ‘message has lines too long for transport‘ error means that your email contains lines of text that exceed the maximum length allowed for sending set by the Outlook email application.
Put simply, your email thread is too long for Outlook to accept it.
The error message may vary depending on your Outlook version, but here is an example of how it looks:
Before you start
🚨This error is caused by the Outlook email application and is unrelated to your email service.
⚠️ If you need to send your email urgently, send it via webmail.
Step by step
There are two main fixes for this error.
The first is the main solution, but if it doesn’t work, try the second one.
1. Delete old replies: Open your email that failed to send and delete some of the older email replies at the bottom of the email thread. Once the older replies are deleted from the email thread, resend your email.
2. Use a different email application: Alternatively, you can use a different email application that allows higher line transport limits. To use a different email app, reference the guides below.
- IMAP and SMTP settings
ℹ️ Note: These settings can be used to add your email to any app that supports IMAP and SMTP.
❗Remember, if Outlook won’t send your email due to restrictions on their end, it doesn’t mean your email is down. You can still access and send your email via webmail.