diff --git a/src/android/__tests__/config.test.ts b/src/android/__tests__/config.test.ts
new file mode 100644
index 0000000..108db51
--- /dev/null
+++ b/src/android/__tests__/config.test.ts
@@ -0,0 +1,40 @@
+import type { ExpoConfig } from "expo/config";
+
+import { withAndroidStringsDependency } from "../strings-dependency";
+
+const config = { name: "test", slug: "test" } as ExpoConfig;
+
+describe("Android config", () => {
+  it.each([undefined, ""])(
+    "rejects a missing CodePush server URL",
+    (CodePushServerURL) => {
+      expect(() =>
+        withAndroidStringsDependency(config, {
+          android: {
+            CodePushDeploymentKey: "android-key",
+            CodePushServerURL: CodePushServerURL as string,
+          },
+          ios: {
+            CodePushDeploymentKey: "ios-key",
+            CodePushServerURL: "https://updates.example.com",
+          },
+        }),
+      ).toThrow(/App Center is retired/);
+    },
+  );
+
+  it("rejects a missing deployment key", () => {
+    expect(() =>
+      withAndroidStringsDependency(config, {
+        android: {
+          CodePushDeploymentKey: "",
+          CodePushServerURL: "https://updates.example.com",
+        },
+        ios: {
+          CodePushDeploymentKey: "ios-key",
+          CodePushServerURL: "https://updates.example.com",
+        },
+      }),
+    ).toThrow(/CodePushDeploymentKey/);
+  });
+});
diff --git a/src/android/strings-dependency.ts b/src/android/strings-dependency.ts
index f9c9b50..43ebd88 100644
--- a/src/android/strings-dependency.ts
+++ b/src/android/strings-dependency.ts
@@ -26,26 +26,24 @@ export const withAndroidStringsDependency: ConfigPlugin<PluginConfigType> = (
   config,
   props,
 ) => {
-  // if (!props?.android?.CodePushServerURL) {
-  //   throw new Error(
-  //       "You need to provide the `CodePushServerURL` Android property for the @config-plugins/react-native-code-push plugin to work."
-  //   );
-  // }
+  if (!props?.android?.CodePushServerURL) {
+    throw new Error(
+      "You need to provide the `CodePushServerURL` Android property for react-native-code-push-plugin to work. App Center is retired, so the default server no longer works.",
+    );
+  }
 
   if (!props?.android?.CodePushDeploymentKey) {
     throw new Error(
-      "You need to provide the `CodePushDeploymentKey` Android property for the @config-plugins/react-native-code-push plugin to work.",
+      "You need to provide the `CodePushDeploymentKey` Android property for react-native-code-push-plugin to work.",
     );
   }
 
   return withStringsXml(config, (xmlProps) => {
-    if (props?.android?.CodePushServerURL) {
-      xmlProps.modResults = setStrings(
-        xmlProps.modResults,
-        "CodePushServerURL",
-        props?.android?.CodePushServerURL,
-      );
-    }
+    xmlProps.modResults = setStrings(
+      xmlProps.modResults,
+      "CodePushServerURL",
+      props.android.CodePushServerURL,
+    );
 
     xmlProps.modResults = setStrings(
       xmlProps.modResults,
diff --git a/src/ios/__tests__/config.test.ts b/src/ios/__tests__/config.test.ts
new file mode 100644
index 0000000..e8fe160
--- /dev/null
+++ b/src/ios/__tests__/config.test.ts
@@ -0,0 +1,40 @@
+import type { ExpoConfig } from "expo/config";
+
+import { withIosInfoPlistDependency } from "../info-plist-dependency";
+
+const config = { name: "test", slug: "test" } as ExpoConfig;
+
+describe("iOS config", () => {
+  it.each([undefined, ""])(
+    "rejects a missing CodePush server URL",
+    (CodePushServerURL) => {
+      expect(() =>
+        withIosInfoPlistDependency(config, {
+          android: {
+            CodePushDeploymentKey: "android-key",
+            CodePushServerURL: "https://updates.example.com",
+          },
+          ios: {
+            CodePushDeploymentKey: "ios-key",
+            CodePushServerURL: CodePushServerURL as string,
+          },
+        }),
+      ).toThrow(/App Center is retired/);
+    },
+  );
+
+  it("rejects a missing deployment key", () => {
+    expect(() =>
+      withIosInfoPlistDependency(config, {
+        android: {
+          CodePushDeploymentKey: "android-key",
+          CodePushServerURL: "https://updates.example.com",
+        },
+        ios: {
+          CodePushDeploymentKey: "",
+          CodePushServerURL: "https://updates.example.com",
+        },
+      }),
+    ).toThrow(/CodePushDeploymentKey/);
+  });
+});
diff --git a/src/ios/info-plist-dependency.ts b/src/ios/info-plist-dependency.ts
index be8357e..eb20681 100644
--- a/src/ios/info-plist-dependency.ts
+++ b/src/ios/info-plist-dependency.ts
@@ -11,23 +11,20 @@ export const withIosInfoPlistDependency: ConfigPlugin<PluginConfigType> = (
   config,
   props,
 ) => {
-  // if (!props?.ios?.CodePushServerURL) {
-  //   throw new Error(
-  //       "You need to provide the `CodePushServerURL` IOS property for the @config-plugins/react-native-code-push plugin to work."
-  //   );
-  // }
+  if (!props?.ios?.CodePushServerURL) {
+    throw new Error(
+      "You need to provide the `CodePushServerURL` iOS property for react-native-code-push-plugin to work. App Center is retired, so the default server no longer works.",
+    );
+  }
 
   if (!props?.ios?.CodePushDeploymentKey) {
     throw new Error(
-      "You need to provide the `CodePushDeploymentKey` IOS property for the @config-plugins/react-native-code-push plugin to work.",
+      "You need to provide the `CodePushDeploymentKey` iOS property for react-native-code-push-plugin to work.",
     );
   }
 
   return withInfoPlist(config, (infoPlistProps) => {
-    if (props?.ios?.CodePushServerURL) {
-      infoPlistProps.modResults.CodePushServerURL =
-        props?.ios?.CodePushServerURL;
-    }
+    infoPlistProps.modResults.CodePushServerURL = props.ios.CodePushServerURL;
 
     infoPlistProps.modResults.CodePushDeploymentKey =
       props.ios.CodePushDeploymentKey;
diff --git a/src/plugin-config.ts b/src/plugin-config.ts
index 0406046..66702b0 100644
--- a/src/plugin-config.ts
+++ b/src/plugin-config.ts
@@ -3,11 +3,11 @@
  */
 export type PluginConfigType = {
   ios: {
-    CodePushServerURL?: string;
+    CodePushServerURL: string;
     CodePushDeploymentKey: string;
   };
   android: {
-    CodePushServerURL?: string;
+    CodePushServerURL: string;
     CodePushDeploymentKey: string;
     CodePushPublicKey?: string;
   };