diff --git a/src/api.ts b/src/api.ts
index eff586c..643d3bb 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -37,6 +37,7 @@ import {
 import {useStore} from "@/store";
 import ChatError from "@/errors/ChatError";
 import {LiveAtlasDynmapServerDefinition, LiveAtlasServerDefinition} from "@/index";
+import ConfigurationError from "@/errors/ConfigurationError";
 
 const titleColours = /§[0-9a-f]/ig;
 
@@ -555,12 +556,12 @@ function buildUpdates(data: Array<any>): DynmapUpdates {
 	return updates;
 }
 
-const validateLiveAtlasConfiguration = (config: any): Promise<Map<string, LiveAtlasServerDefinition>> => {
+const validateLiveAtlasConfiguration = (config: any): Map<string, LiveAtlasServerDefinition> => {
 	const check = '\nCheck your server configuration in index.html is correct.',
 		result = new Map<string, LiveAtlasServerDefinition>();
 
 	if (!Object.keys(config).length) {
-		return Promise.reject(`No servers defined in LiveAtlas configuration.`);
+		throw new ConfigurationError(`No servers defined. ${check}`);
 	}
 
 	for (const server in config) {
@@ -570,35 +571,35 @@ const validateLiveAtlasConfiguration = (config: any): Promise<Map<string, LiveAt
 
 		const serverConfig = config[server];
 
+		if (!serverConfig || serverConfig.constructor !== Object || !Object.keys(serverConfig).length) {
+			throw new ConfigurationError(`Server '${server}': Configuration missing. ${check}`);
+		}
+
 		serverConfig.id = server;
 		serverConfig.type = 'dynmap';
 
-		if (!serverConfig || serverConfig.constructor !== Object) {
-			return Promise.reject(`Server '${server}' has an invalid configuration. ${check}`);
-		}
-
 		if (!serverConfig.dynmap || serverConfig.dynmap.constructor !== Object) {
-			return Promise.reject(`Server '${server}' has an invalid configuration. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap configuration object missing. ${check}`);
 		}
 
 		if (!serverConfig.dynmap.configuration) {
-			return Promise.reject(`Server '${server}' has no dynmap configuration URL. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap configuration URL missing. ${check}`);
 		}
 
 		if (!serverConfig.dynmap.update) {
-			return Promise.reject(`Server '${server}' has no dynmap update URL. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap update URL missing. ${check}`);
 		}
 
 		if (!serverConfig.dynmap.markers) {
-			return Promise.reject(`Server '${server}' has no dynmap markers URL. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap markers URL missing. ${check}`);
 		}
 
 		if (!serverConfig.dynmap.tiles) {
-			return Promise.reject(`Server '${server}' has no dynmap tiles URL. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap tiles URL missing. ${check}`);
 		}
 
 		if (!serverConfig.dynmap.sendmessage) {
-			return Promise.reject(`Server '${server}' has no dynmap sendmessage URL. ${check}`);
+			throw new ConfigurationError(`Server '${server}': Dynmap sendmessage URL missing. ${check}`);
 		}
 
 		if(serverConfig.url) {
@@ -606,7 +607,7 @@ const validateLiveAtlasConfiguration = (config: any): Promise<Map<string, LiveAt
 			a.href = serverConfig.url;
 
 			if(a.origin !== window.location.origin) {
-				return Promise.reject(`Server '${server}'s URL doesn't match LiveAtlas' origin. ${check}`);
+				throw new ConfigurationError(`Server '${server}': URL doesn't match LiveAtlas origin. ${check}`);
 			}
 
 			serverConfig.url = a.pathname;
@@ -617,34 +618,34 @@ const validateLiveAtlasConfiguration = (config: any): Promise<Map<string, LiveAt
 		result.set(server, serverConfig);
 	}
 
-	return Promise.resolve(result);
+	return result;
 };
 
-const validateDynmapConfiguration = (config: DynmapUrlConfig): Promise<Map<string, LiveAtlasDynmapServerDefinition>> => {
+const validateDynmapConfiguration = (config: DynmapUrlConfig): Map<string, LiveAtlasDynmapServerDefinition> => {
 	const check = '\nCheck your standalone/config.js file exists and is being loaded correctly.';
 
 	if (!config) {
-		return Promise.reject(`Dynmap configuration is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap configuration is missing. ${check}`);
 	}
 
 	if (!config.configuration) {
-		return Promise.reject(`Dynmap configuration URL is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap configuration URL is missing. ${check}`);
 	}
 
 	if (!config.update) {
-		return Promise.reject(`Dynmap update URL is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap update URL is missing. ${check}`);
 	}
 
 	if (!config.markers) {
-		return Promise.reject(`Dynmap markers URL is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap markers URL is missing. ${check}`);
 	}
 
 	if (!config.tiles) {
-		return Promise.reject(`Dynmap tiles URL is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap tiles URL is missing. ${check}`);
 	}
 
 	if (!config.sendmessage) {
-		return Promise.reject(`Dynmap sendmessage URL is missing. ${check}`);
+		throw new ConfigurationError(`Dynmap sendmessage URL is missing. ${check}`);
 	}
 
 	const result = new Map<string, LiveAtlasDynmapServerDefinition>();
@@ -655,7 +656,7 @@ const validateDynmapConfiguration = (config: DynmapUrlConfig): Promise<Map<strin
 		dynmap: config
 	});
 
-	return Promise.resolve(result);
+	return result;
 };
 
 async function fetchJSON(url: string) {
@@ -682,12 +683,16 @@ async function fetchJSON(url: string) {
 
 
 export default {
-	validateConfiguration(): Promise<Map<string, LiveAtlasServerDefinition>> {
-		if (typeof window.liveAtlasConfig.servers !== 'undefined') {
-			return validateLiveAtlasConfiguration(window.liveAtlasConfig.servers);
+	validateConfiguration(): Map<string, LiveAtlasServerDefinition> {
+		if (!window.liveAtlasConfig) {
+			throw new ConfigurationError(`Configuration object is missing`);
 		}
 
-		return validateDynmapConfiguration(window.config.url ?? null);
+		if (typeof window.liveAtlasConfig.servers !== 'undefined') {
+			return validateLiveAtlasConfiguration(window.liveAtlasConfig.servers || {});
+		}
+
+		return validateDynmapConfiguration(window.config?.url || null);
 	},
 
 	async getConfiguration(): Promise<DynmapConfigurationResponse> {
diff --git a/src/errors/ConfigurationError.ts b/src/errors/ConfigurationError.ts
new file mode 100644
index 0000000..a218015
--- /dev/null
+++ b/src/errors/ConfigurationError.ts
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 James Lyne
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+export default class ConfigurationError extends Error {
+	constructor(message: string) {
+		super(message);
+		this.name = "ConfigurationError";
+	}
+}
\ No newline at end of file
diff --git a/src/main.ts b/src/main.ts
index 9926929..7ec999e 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -85,7 +85,9 @@ window.showSplashError = function(message: string, fatal: boolean, attempts: num
 
 console.info(`LiveAtlas version ${store.state.version} - https://github.com/JLyne/LiveAtlas`);
 
-API.validateConfiguration().then((config) => {
+try {
+	const config = API.validateConfiguration();
+
 	store.commit(MutationTypes.SET_SERVERS, config);
 
 	if(config.size > 1) {
@@ -106,7 +108,7 @@ API.validateConfiguration().then((config) => {
 
 	// app.config.performance = true;
 	app.mount('#app');
-}).catch(e => {
+} catch(e) {
 	console.error('LiveAtlas configuration is invalid: ', e);
 	window.showSplashError('LiveAtlas configuration is invalid\n' + e, true);
-});
+}