diff -Naur node_modules/granax/lib/controller.js node_patch/granax/lib/controller.js
--- node_modules/granax/lib/controller.js	1985-10-26 09:15:00.000000000 +0100
+++ node_patch/granax/lib/controller.js	2018-11-18 17:29:52.470853999 +0100
@@ -177,6 +177,7 @@
 
     switch (code.toString()[0]) {
       case '2':
+        if (this._stack.length == 0) { console.error("Stack is empty, bug!"); break; }
         let { method, callback } = this._stack.pop();
         let parsed = replies[method]
           ? replies[method](lines)
@@ -185,6 +186,7 @@
         break;
       case '4':
       case '5':
+        if (this._stack.length == 0) { console.error("Stack is empty, bug!"); break; }
         this._stack.pop().callback(new Error(lines[0]));
         break;
       case '6':