How to fix SMTP error: Message size exceeds server limit in Roundcube?

Are you getting SMTP error message, ‘Size exceeds server limit’ in Roundcube Webmail? Does it cause a problem and do you want to fix it?

What exactly does this SMTP error message: ‘Size exceeds server limit’ mean?

Are you facing issues with large email attachments? Do they surpass the upload limit despite the fact that the attachment size is within the limit?

You’ve arrived at the right location!

Most emails are encrypted in Base64, before they are sent out. This increases the email’s size and may trigger the ModSec upload limit regulations. Even though the email size appears to be below the limit when sent, this prevents it from being sent.

So, how can we fix an SMTP error problem that says the message size exceeds the server limit in Roundcube webmail?

Increasing the message size limit in the Exim Configuration Manager is a good technique to fix this error. To do this, please follow the steps recommended below.

  1. To begin with, navigate to Service Configuration.
  2. Then, go to Exim Configuration Manager.
  3. After that, go to Advanced Editor.
  4. Next, select CONFIG sections.
  5. Finally, select message_size_limit.

This should fix SMTP error message, ‘Size exceeds server limit’ in Roundcube Webmail. Also note that, you can add any message size limit, as a new configuration element in the CONFIG section, if it is not automatically listed.

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