diff --git a/src/middleware/pnid.ts b/src/middleware/pnid.ts
index cb9776e..63b8554 100644
--- a/src/middleware/pnid.ts
+++ b/src/middleware/pnid.ts
@@ -6,6 +6,7 @@ import { HydratedPNIDDocument } from '@/types/mongoose/pnid';
 
 async function PNIDMiddleware(request: express.Request, response: express.Response, next: express.NextFunction): Promise<void> {
 	const authHeader = getValueFromHeaders(request.headers, 'authorization');
+	const email = getValueFromHeaders(request.headers, 'x-nintendo-email');
 
 	if (!authHeader || !(authHeader.startsWith('Bearer') || authHeader.startsWith('Basic'))) {
 		return next();
@@ -53,6 +54,19 @@ async function PNIDMiddleware(request: express.Request, response: express.Respon
 		return;
 	}
 
+	if (email != undefined && pnid.email.address !== email) {
+		response.status(401).send(xmlbuilder.create({
+			errors: {
+				error: {
+					code: '1105',
+					message: 'Email address, username, or password, is not valid'
+				}
+			}
+		}).end());
+
+		return;
+	}
+
 	if (pnid.deleted) {
 		response.status(400).send(xmlbuilder.create({
 			errors: {
@@ -84,4 +98,4 @@ async function PNIDMiddleware(request: express.Request, response: express.Respon
 	return next();
 }
 
-export default PNIDMiddleware;
\ No newline at end of file
+export default PNIDMiddleware;