diff --git a/app/admin.py b/app/admin.py
index f1befee..a67ee90 100644
--- a/app/admin.py
+++ b/app/admin.py
@@ -118,6 +118,11 @@ class EnvCredentialProvider(Provider):
                 status_code=status_code,
             )
 
+    @staticmethod
+    def _admin_home(request: Request) -> str:
+        """Use trailing slash to avoid mount redirect (which may emit absolute host)."""
+        return request.app.admin_path.rstrip("/") + "/"
+
     async def login_view(self, request: Request):
         return self._template_response(
             request=request,
@@ -150,7 +155,7 @@ class EnvCredentialProvider(Provider):
                 },
             )
 
-        response = RedirectResponse(url=request.app.admin_path, status_code=HTTP_303_SEE_OTHER)
+        response = RedirectResponse(url=self._admin_home(request), status_code=HTTP_303_SEE_OTHER)
         expire = self.expire_seconds
         if remember_me == "on":
             expire = max(self.expire_seconds, 3600 * 24 * 30)
@@ -183,7 +188,7 @@ class EnvCredentialProvider(Provider):
         request.state.admin = admin
 
         if path.endswith(self.login_path) and admin:
-            return RedirectResponse(url=request.app.admin_path, status_code=HTTP_303_SEE_OTHER)
+            return RedirectResponse(url=self._admin_home(request), status_code=HTTP_303_SEE_OTHER)
 
         return await call_next(request)