This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Error 5.3.4 552 5.3.4

  • 2 cavab
  • 2 have this problem
  • 9 views
  • Last reply by freudet

more options

Hello. I'm trying to forward an email to about 20 people from an Outlook address in Thunderbird. The email has 1 MB attachments. After I click send this error comes out : "An error occurred while sending mail. The mail server responded: 5.3.4 552 5.3.4 Header size exceeds fixed maximum size. " I've been googling but couldn't find any solution. I've even tried sending the same email without any attachments and it's still not working. Just yesterday I've been forwarding an email from the same address without any attachments to the same people and it worked well.

Will be grateful for any help!

Hello. I'm trying to forward an email to about 20 people from an Outlook address in Thunderbird. The email has 1 MB attachments. After I click send this error comes out : "An error occurred while sending mail. The mail server responded: 5.3.4 552 5.3.4 Header size exceeds fixed maximum size. " I've been googling but couldn't find any solution. I've even tried sending the same email without any attachments and it's still not working. Just yesterday I've been forwarding an email from the same address without any attachments to the same people and it worked well. Will be grateful for any help!

All Replies (2)

more options

You can try to create a mailing list. http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Create_Mailing_List

Alternatively try to reduce the number of recipients or talk to your email provider. The error message is from their server.

more options

I've been sending it to a mailing list. Thank you, I will ask them then.