diff --git a/classes/Tools.php b/classes/Tools.php
index 34c1229db..f5ca5a939 100644
--- a/classes/Tools.php
+++ b/classes/Tools.php
@@ -267,6 +267,9 @@ class ToolsCore
 		// $_SERVER['SSL'] exists only in some specific configuration
 		if (isset($_SERVER['SSL']))
 			return ($_SERVER['SSL'] == 1 || strtolower($_SERVER['SSL']) == 'on');
+		// $_SERVER['REDIRECT_HTTPS'] exists only in some specific configuration
+		if (isset($_SERVER['REDIRECT_HTTPS']))
+			return ($_SERVER['REDIRECT_HTTPS'] == 1 || strtolower($_SERVER['REDIRECT_HTTPS']) == 'on');
 
 		return false;
 	}
diff --git a/classes/pdf/HTMLTemplateOrderSlip.php b/classes/pdf/HTMLTemplateOrderSlip.php
index 06b8b2e23..70f395b75 100644
--- a/classes/pdf/HTMLTemplateOrderSlip.php
+++ b/classes/pdf/HTMLTemplateOrderSlip.php
@@ -211,6 +211,8 @@ class HTMLTemplateOrderSlipCore extends HTMLTemplateInvoice
 		if ($ecotax)
 			foreach ($tmp_tax_infos as $rate => &$row)
 			{
+				if (!isset($ecotax[$rate]))
+					continue
 				$row['total_price_tax_excl'] -= $ecotax[$rate]['ecotax_tax_excl'];
 				$row['total_amount'] -= ($ecotax[$rate]['ecotax_tax_incl'] - $ecotax[$rate]['ecotax_tax_excl']);
 			}