diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index b64c354..69d1b32 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -220,7 +220,7 @@
 
 #if defined(MBEDTLS_THREADING_C)
     if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
-        return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR ,
+        return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR,
                 MBEDTLS_ERR_THREADING_MUTEX_ERROR ) );
 #endif