diff --git a/lex.js b/lex.js
index c61bcf1..751e2dc 100644
--- a/lex.js
+++ b/lex.js
@@ -24,6 +24,21 @@ module.exports.create = function (opts) {
     var ports = port;
     var servers = [];
 
+    function explainError(e) {
+      console.error('Error:' + e.message);
+      if ('EACCES' === e.errno) {
+        console.error("You don't have prmission to access '" + e.address + ":" + e.port + "'.");
+        console.error("You probably need to use \"sudo\" or \"sudo setcap 'cap_net_bind_service=+ep' $(which node)\"");
+        return;
+      }
+      if ('EADDRINUSE' === e.errno) {
+        console.error("'" + e.address + ":" + e.port + "' is already being used by some other program.");
+        console.error("You probably need to stop that program or restart your computer.");
+        return;
+      }
+      console.error(e.code + ": '" + e.address + ":" + e.port + "'");
+    }
+
     if (!plainPorts) {
       plainPorts = 80;
     }
@@ -37,20 +52,30 @@ module.exports.create = function (opts) {
     }
 
     plainPorts.forEach(function (p) {
-      promises.push(new PromiseA(function (resolve, reject) {
+      if (!(parseInt(p, 10) >= 0)) { console.warn("'" + p + "' doesn't seem to be a valid port number for http"); }
+      promises.push(new PromiseA(function (resolve) {
         require('http').createServer(le.middleware(require('redirect-https')())).listen(p, function () {
-          console.log("Handling ACME challenges and redirecting to https on plain port " + p);
+          console.log("Success! Bound to port '" + p + "' to handle ACME challenges and redirect to https");
           resolve();
-        }).on('error', reject);
+        }).on('error', function (e) {
+          console.log("Did not successfully create http server and bind to port '" + p + "':");
+          explainError(e);
+          process.exit(0);
+        });
       }));
     });
 
     ports.forEach(function (p) {
-      promises.push(new PromiseA(function (resolve, reject) {
+      if (!(parseInt(p, 10) >= 0)) { console.warn("'" + p + "' doesn't seem to be a valid port number for https"); }
+      promises.push(new PromiseA(function (resolve) {
         var server = require('https').createServer(le.httpsOptions, le.middleware(le.app)).listen(p, function () {
-          console.log("Handling ACME challenges and serving https " + p);
+          console.log("Success! Serving https on port '" + p + "'");
           resolve();
-        }).on('error', reject);
+        }).on('error', function (e) {
+          console.log("Did not successfully create https server and bind to port '" + p + "':");
+          explainError(e);
+          process.exit(0);
+        });
         servers.push(server);
       }));
     });