PHP mail() Compatibility Mode

Arclab® Web Form Builder

Compatibility Mode

When sending the email directly via the website, there may be problems with the email due to various server installations and mail transfer agents. This can have the effect that instead of the email, the source text is displayed or an unreadable attachment is added. In very rare cases, the email is not delivered at all. You can choose the "PHP mail() Compatibility Mode" in the "Email Options".


Please note that the "PHP mail() Compatibility Mode" only helps with a broken email, ie illegible source code or characters are displayed instead of the text.


Switch to "Email and Database", select a task and click on "Edit" (or double-click on the task).
In the email editor click on "Email Options", switch to "Email Encoding" and check the "PHP mail() Compatibility Mode".


PHP mail() Compatibility Mode


First use "(A)", if it still does not work try (B).


Technical Background:
Some Unix mail transfer agents violate the RFC by replacing LF by CRLF automatically which leads to a broken email encoding (double CR).
Only use this option if the "CRLF (RFC Standard)" is not working.


If both options did not solve the problem, there might be another reason why the email is broken (see below).
If the internal mail function "PHP mail()" is not working properly on your website/server, you should try sending the email using an SMTP (mail) server.

error_outline  Other Issues for a Broken Email

If you have already tried the PHP mail() compatibility modes (A) and (B), but they were unsuccessful, please reset the mode to "CRLF (RFC Standard)" first.


  • Problem: Missing line-breaks in plain-text messages in MS Outlook
    See: FAQ: Missing line breaks in plain-text messages in MS Outlook

  • Problem: "magic_quotes" might be turned on
    This only happens in rare cases, mostly with very old php versions.

    magic_quotes are DEPRECATED and should no longer been used.
    Please disable magic_quotes in your PHP configuration to fix this issue.
    Please take a look at the manual for details.

  • Problem: File uploads/attachments
    Try to submit the form without adding an attachment to the email.
    In some rare cases, the attachments are cut off due to a size restriction on the website/server, which could break the encoding.

  • Problem: PHP mail() function is broken
    If the internal mail function "PHP mail()" is not working properly on your website/server, you can try sending the email using an external SMTP (mail) server as described below.

error_outline  Use SMTP instead of the internal Mail Function "PHP mail()"

If the internal mail function "PHP mail()" is not working click on "Edit Server and Sender" and use "Send the Email via an Email Account - SMTP Server". In this mode the email is sent using the specified mail server instead of the internal mail function.

SMTP Mail Server