error MESSAGE HAS LINES TOO LONG TO TRANSPORT

CARLOS GALLEGO

• September 26, 2025 07:34

Since last week updates, a lot of users of my servers are having problems to send, reply, or forward some email messages.

Destination servers returns a mail relivery error with this message:
MESSAGE HAS LINES TOO LONG TO TRANSPORT

I happens one every week usually, but now, it happens hundreds of times every day in all my cpanel servers.

the problems is caused by spamassassin, it add a header called "X-Ham-Report". If you open some of the failed messages, you can see that this is the only line longer tan 100 characters. Sometimes this line have thousands of characters breaking RFC standard.

the solution is to disable X-Ham-Report header in spamassassin.

• 

  ffeingol

  • September 26, 2025 11:50

  This is a bit old, but does it help: https://support.cpanel.net/hc/en-us/articles/4420121088919-Exim-4-95-message-has-lines-too-long-for-transport-Error

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  CARLOS GALLEGO

  • September 26, 2025 12:27
  • Edited

  Hi!
  I've read some messages about this error before to post.
  
  i've seen this error before in my servers, but, if it happens once a week, i can say that it's not my fault, and outlook is a bullshit bla bla bla...
  
  but it was happening hundreds of times now.
  
  all my servers are updated to last version of cpanel, and no, the users are not sending this emails using Outlook. The emails that causes the problem are sent from contact forms, gmail web client, gmail android client, thunderbird... 
  
  the problems happens in some "normal" emails, but in 99% of cases the problem happens when a message is affected by a cpanel's forward rule.
  
  Increase the lenght of 

  message_linelength_limit = 2048

  is not the right way to solve this, because it can cause more collateral problems in the email server, and since yesterday it was working without problems.
  
  Spamassassin adds this headers:

   
  the only line in all the messages that exceed the 100 characters limit (without line breaks!) is the X-Ham-report line, that includes all the previos headers that spamassassin have scaned, all concatened without spaces or line breaks. It you forward this message to another email address, X-Ham_report line increases the line lenght exponentially.
  
  it have no sense to increase the allowed line lenght in all the server breaking the RFC standards, only because spamassassin is inserting a bad-formated header in messages.
  
  i dont know if spamassassin rules have been updated, but, as i said, different servers have been started to fail al same time.
  
  now, i've removed this header (hacking .cnf templates), but i'm sure that this fail can return every time that my changes will be overwrited by cpanel's config file regeneration.
  
  

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• 

  cPRex Jurassic Moderator

  • September 26, 2025 17:11

  This is likely related to this case:

  https://support.cpanel.net/hc/en-us/articles/35188116024215-X-Ham-Report-header-due-to-RFC-2047-compliance

  can you try the fix mentioned there to see if that helps your situation?

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