diff --git a/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/BinaryFileUploadStreamObserver.java b/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/BinaryFileUploadStreamObserver.java
index ae9c6ad05defbedc8562010410610d5b9b328ef4..c9749d86520589cbed756e90f39e62606542e3bf 100644
--- a/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/BinaryFileUploadStreamObserver.java
+++ b/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/BinaryFileUploadStreamObserver.java
@@ -58,6 +58,7 @@ public class BinaryFileUploadStreamObserver<ReqT, R> implements ClientResponseOb
 
 	@Override
 	public void onError(Throwable t) {
+		LOG.error("Error on uploading file. Completing Future.", t);
 		future.completeExceptionally(t);
 	}
 
diff --git a/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/GrpcFileUploadUtils.java b/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/GrpcFileUploadUtils.java
index 7554b3e1e77ef6fbe03ce2c72bd2f885540f7665..c9dc311ec7d52bf106ab2eb174a77f583b7d0c74 100644
--- a/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/GrpcFileUploadUtils.java
+++ b/kop-common-lib/src/main/java/de/itvsh/kop/common/binaryfile/GrpcFileUploadUtils.java
@@ -48,7 +48,7 @@ import lombok.extern.log4j.Log4j2;
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class GrpcFileUploadUtils {
 
-	static final int CHUNK_SIZE = 255 * 1024;
+	static final int CHUNK_SIZE = 4 * 1024;
 
 	/*
 	 * Q = Request Type; S = Response Type