diff --git a/spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/FunctionInvoker.java b/spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/FunctionInvoker.java
index 8081c234c..a60494169 100644
--- a/spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/FunctionInvoker.java
+++ b/spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/FunctionInvoker.java
@@ -187,7 +187,7 @@ public class FunctionInvoker<I, O> {
 
 	@SuppressWarnings("unchecked")
 	private Object convertOutputIfNecessary(Object input, Object output) {
-		if (input instanceof HttpRequestMessage) {
+		if (input != null && input instanceof HttpRequestMessage) {
 			HttpRequestMessage<I> requestMessage = (HttpRequestMessage<I>) input;
 			Map<String, Object> headers = null;
 			if (output instanceof Message) {