diff --git a/src/main.ts b/src/main.ts
index 819eadd..414fdee 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -17,6 +17,11 @@ if (!process.env.ADMINS) {
     process.exit(1);
 }
 
+if (!process.env.ORIGIN) {
+    console.error("no origin found");
+    process.exit(1);
+}
+
 const FILESIZE = process.env.FILESIZE_LIMIT
 if (!FILESIZE) {
     console.error("no file size detected");
@@ -28,10 +33,10 @@ if (!FILESIZE) {
 
 const PORT = process.env.PORT
 if (!PORT) {
-    console.error("no file size detected");
+    console.error("no port detected");
     process.exit(1);
 } else if (isNaN(Number(PORT)) && FILESIZE.trim() !== '') {
-    console.error("file size cannot be parsed.");
+    console.error("port cannot be parsed.");
     process.exit(1);
 }
 
@@ -57,7 +62,7 @@ fastify.register(fastifyOauth2, {
     },
     scope: ["identify"],
     startRedirectPath: '/login',
-    callbackUri: req => `${req.protocol}://${req.host}/login/callback`,
+    callbackUri: req => `${process.env.ORIGIN}/login/callback`,
 })
 
 fastify.get('/login/callback', async function (request, reply) {