diff --git a/src/mms/iso_presentation/iso_presentation.c b/src/mms/iso_presentation/iso_presentation.c
index e2ee12a7..c4f2f64e 100644
--- a/src/mms/iso_presentation/iso_presentation.c
+++ b/src/mms/iso_presentation/iso_presentation.c
@@ -856,9 +856,7 @@ IsoPresentation_createAbortUserMessage(IsoPresentation* self, BufferChain writeB
 {
     int contentLength = 0;
 
-    contentLength = +encodeUserData(NULL, 0, payload, false, self->acseContextId);
-
-    contentLength += BerEncoder_determineLengthSize(contentLength) + 1;
+    contentLength += encodeUserData(NULL, 0, payload, false, self->acseContextId);
 
     uint8_t* buffer = writeBuffer->buffer;
     int bufPos = 0;