diff --git a/htdocs/admin/mails.php b/htdocs/admin/mails.php
index d05518374c1..ed290060370 100644
--- a/htdocs/admin/mails.php
+++ b/htdocs/admin/mails.php
@@ -619,6 +619,12 @@ else
 	print '</div>';
 
 
+	if ($conf->global->MAIN_MAIL_SENDMODE == 'mail')
+	{
+        $text = $langs->trans("WarningPHPMail");
+	    print info_admin($text);
+	}
+	    
 	// Run the test to connect
 	if ($action == 'testconnect')
 	{
diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index 82ff69fe88a..c57ea45858a 100644
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -411,6 +411,7 @@ ModuleCompanyCodePanicum=Return an empty accountancy code.
 ModuleCompanyCodeDigitaria=Accountancy code depends on third party code. The code is composed of the character "C" in the first position followed by the first 5 characters of the third party code.  
 Use3StepsApproval=By default, Purchase Orders need to be created and approved by 2 different users (one step/user to create and one step/user to approve. Note that if user has both permission to create and approve, one step/user will be enough). You can ask with this option to introduce a third step/user approval, if amount is higher than a dedicated value (so 3 steps will be necessary: 1=validation, 2=first approval and 3=second approval if amount is enough).<br>Set this to empty if one approval (2 steps) is enough, set it to a very low value (0.1) if a second approval (3 steps) is always required.  
 UseDoubleApproval=Use a 3 steps approval when amount (without tax) is higher than...
+WarningPHPMail=WARNING: Some email providers (like Yahoo) does not allow you to send an email from another server than the Yahoo server if the email address used as a sender is your Yahoo email (like myemail@yahoo.com, myemail@yahoo.fr, ...). Your current setup use the server of the application to send email, so some recipients (the one compatible with the restrictive DMARC protocol), will ask Yahoo if they can accept your email and Yahoo will respond "no" because the server is not a server owned by Yahoo, so few of your sent Emails may not be accepted.<br>If your Email provider (like Yahoo) has this restriction, you must change Email setup to choose the other method "SMTP server" and enter the SMTP server and credentials provided by your Email provider (ask your EMail provider to get SMTP credentials for your account). 
 
 # Modules
 Module0Name=Users & groups