diff --git a/src/main/java/de/mrbesen/telegram/MessageBuilder.java b/src/main/java/de/mrbesen/telegram/MessageBuilder.java
index c4fcf78..99e2e0b 100644
--- a/src/main/java/de/mrbesen/telegram/MessageBuilder.java
+++ b/src/main/java/de/mrbesen/telegram/MessageBuilder.java
@@ -283,6 +283,8 @@ public class MessageBuilder {
 		Animation;
 		
 		public static Attachment getForFileExt(String extention) {
+			if(extention == null) return Document;
+
 			if(extention.startsWith("."))
 				extention = extention.substring(1);