diff --git a/Troubleshooting-PHP-FPM-and-FastCGI.md b/Troubleshooting-PHP-FPM-and-FastCGI.md
index 9743c59..110ceb2 100644
--- a/Troubleshooting-PHP-FPM-and-FastCGI.md
+++ b/Troubleshooting-PHP-FPM-and-FastCGI.md
@@ -19,7 +19,8 @@ Sample error:
 ```
 [ERROR 502 /index.php] malformed MIME header line: Primary script unknown
 ```
-Update to Caddy 0.8.1. This will either fix it or get you a more descriptive error message.
+Update to Caddy 0.8.1. This will either fix it or get you a more descriptive error message. 
+On Unix-like systems this issue can also occur because Caddy and php-fpm aren't running under the same user/group. Make sure you run them under the same user/group and give proper permissions to the document root folder (chmod).
 
 ## Connection refused
 Sample error: