diff --git a/package.json b/package.json
index a94f981..76b9fad 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "@babel/preset-env": "^7.16.5",
     "acorn": "^8.6.0",
     "babel-loader": "^8.2.3",
+    "cors": "^2.8.5",
     "express": "^4.17.1",
     "express-force-https": "^1.0.0",
     "express-rate-limit": "^6.0.1",
diff --git a/server/api/GamesAPI.js b/server/api/GamesAPI.js
index 677c2b4..c65d4d5 100644
--- a/server/api/GamesAPI.js
+++ b/server/api/GamesAPI.js
@@ -4,6 +4,7 @@ const debugMode = Array.from(process.argv.map((arg) => arg.trim().toLowerCase())
 const logger = require('../modules/Logger')(debugMode);
 const GameManager = require('../modules/GameManager.js');
 const rateLimit = require('express-rate-limit').default
+const globals = require('../config/globals');
 
 const gameManager = new GameManager().getInstance();
 
@@ -19,7 +20,7 @@ if (process.env.NODE_ENV.trim() === 'production') { // in prod, limit clients to
 }
 
 router.post('/create', function (req, res) {
-    logger.debug('Received request to create new game: ' + JSON.stringify(req.body, null, 4));
+    logger.trace('Received request to create new game: ' + JSON.stringify(req.body, null, 4));
     const gameCreationPromise = gameManager.createGame(req.body, false);
     gameCreationPromise.then((result) => {
         if (result instanceof Error) {
@@ -27,6 +28,10 @@ router.post('/create', function (req, res) {
         } else {
             res.send(result); // game was created successfully, and access code was returned
         }
+    }).catch((e) => {
+        if (e === globals.ERROR_MESSAGE.BAD_CREATE_REQUEST) {
+            res.status(400).send(globals.ERROR_MESSAGE.BAD_CREATE_REQUEST);
+        }
     });
 });
 
diff --git a/server/config/globals.js b/server/config/globals.js
index 48dee1d..131659e 100644
--- a/server/config/globals.js
+++ b/server/config/globals.js
@@ -33,7 +33,8 @@ const globals = {
         SPECTATOR: "spectator"
     },
     ERROR_MESSAGE: {
-        GAME_IS_FULL: "This game is full"
+        GAME_IS_FULL: "This game is full",
+        BAD_CREATE_REQUEST: "Game has invalid options."
     },
     EVENTS: {
         PLAYER_JOINED: "playerJoined",
diff --git a/server/main.js b/server/main.js
index 8b19615..fedfe26 100644
--- a/server/main.js
+++ b/server/main.js
@@ -4,6 +4,7 @@ const https = require('https');
 const path = require('path');
 const fs = require('fs');
 const app = express();
+const cors = require('cors')
 const bodyParser = require('body-parser');
 const GameManager = require('./modules/GameManager.js');
 const globals = require('./config/globals');
@@ -66,6 +67,12 @@ app.set('port', port);
 let io;
 
 if (process.env.NODE_ENV.trim() === 'development') {
+    const corsOptions = {
+        origin: "http://localhost:" + port,
+        optionsSuccessStatus: 200,
+        methods: ["GET", "POST"]
+    }
+    app.use(cors(corsOptions));
     io = require("socket.io")(main, {
         cors: {
             origin: "http://localhost:" + port,
@@ -75,6 +82,13 @@ if (process.env.NODE_ENV.trim() === 'development') {
         }
     });
 } else {
+    const corsOptions = {
+        origin: ["https://playwerewolf.uk.r.appspot.com"],
+        methods: ["GET", "POST"],
+        allowedHeaders: ["Content-Type", "X-Requested-With", "Accept"],
+        optionsSuccessStatus: 200,
+    }
+    app.use(cors(corsOptions));
     io = require("socket.io")(main, {
         cors: {
             origin: ["https://playwerewolf.uk.r.appspot.com", "wss://playwerewolf.uk.r.appspot.com"],
diff --git a/server/modules/GameManager.js b/server/modules/GameManager.js
index f93466f..35ce963 100644
--- a/server/modules/GameManager.js
+++ b/server/modules/GameManager.js
@@ -176,7 +176,7 @@ class GameManager {
         const expectedKeys = ['deck', 'hasTimer', 'timerParams'];
         if (typeof gameParams !== 'object' || expectedKeys.some((key) => !Object.keys(gameParams).includes(key))) {
             this.logger.error('Tried to create game with invalid options: ' + JSON.stringify(gameParams));
-            return Promise.reject('Tried to create game with invalid options: ' + gameParams);
+            return Promise.reject(globals.ERROR_MESSAGE.BAD_CREATE_REQUEST);
         } else {
             // to avoid excessive memory build-up, every time a game is created, check for and purge any stale games.
             pruneStaleGames(this.activeGameRunner.activeGames, this.activeGameRunner.timerThreads, this.logger);