diff --git a/htdocs/public/payment/paymentko.php b/htdocs/public/payment/paymentko.php
index bed4a3d63f0..d206dc5831f 100644
--- a/htdocs/public/payment/paymentko.php
+++ b/htdocs/public/payment/paymentko.php
@@ -173,7 +173,7 @@ if (!empty($_SESSION['ipaddress'])) {      // To avoid to make action twice
 		$companylangs->setDefaultLang($mysoc->default_lang);
 		$companylangs->loadLangs(array('main', 'members', 'bills', 'paypal', 'paybox'));
 
-		$from = $conf->global->MAILING_EMAIL_FROM;
+		$from = !empty($conf->global->MAILING_EMAIL_FROM) ? $conf->global->MAILING_EMAIL_FROM : getDolGlobalString("MAIN_MAIL_EMAIL_FROM");
 		$sendto = $sendemail;
 
 		$urlback = $_SERVER["REQUEST_URI"];
diff --git a/htdocs/public/payment/paymentok.php b/htdocs/public/payment/paymentok.php
index 154e4606cd5..241fa09dabc 100644
--- a/htdocs/public/payment/paymentok.php
+++ b/htdocs/public/payment/paymentok.php
@@ -1299,7 +1299,7 @@ if ($ispaymentok) {
 							$texttosend = make_substitutions($msg, $substitutionarray, $outputlangs);
 
 							$sendto = $attendeetovalidate->email;
-							$from = $conf->global->MAILING_EMAIL_FROM;
+							$from = !empty($conf->global->MAILING_EMAIL_FROM) ? $conf->global->MAILING_EMAIL_FROM : getDolGlobalString("MAIN_MAIL_EMAIL_FROM");
 							$urlback = $_SERVER["REQUEST_URI"];
 
 							$ishtml = dol_textishtml($texttosend); // May contain urls
@@ -1596,7 +1596,7 @@ if ($ispaymentok) {
 		$companylangs->loadLangs(array('main', 'members', 'bills', 'paypal', 'paybox'));
 
 		$sendto = $sendemail;
-		$from = $conf->global->MAILING_EMAIL_FROM;
+		$from = !empty($conf->global->MAILING_EMAIL_FROM) ? $conf->global->MAILING_EMAIL_FROM : getDolGlobalString("MAIN_MAIL_EMAIL_FROM");
 		// Define $urlwithroot
 		$urlwithouturlroot = preg_replace('/'.preg_quote(DOL_URL_ROOT, '/').'$/i', '', trim($dolibarr_main_url_root));
 		$urlwithroot = $urlwithouturlroot.DOL_URL_ROOT; // This is to use external domain name found into config file
@@ -1724,7 +1724,7 @@ if ($ispaymentok) {
 		$companylangs->loadLangs(array('main', 'members', 'bills', 'paypal', 'paybox'));
 
 		$sendto = $sendemail;
-		$from = $conf->global->MAILING_EMAIL_FROM;
+		$from = !empty($conf->global->MAILING_EMAIL_FROM) ? $conf->global->MAILING_EMAIL_FROM : getDolGlobalString("MAIN_MAIL_EMAIL_FROM");
 		// Define $urlwithroot
 		$urlwithouturlroot = preg_replace('/'.preg_quote(DOL_URL_ROOT, '/').'$/i', '', trim($dolibarr_main_url_root));
 		$urlwithroot = $urlwithouturlroot.DOL_URL_ROOT; // This is to use external domain name found into config file