diff --git a/Functions/Authentication.cs b/Functions/Authentication.cs
index 95083dc..ee1e723 100644
--- a/Functions/Authentication.cs
+++ b/Functions/Authentication.cs
@@ -53,12 +53,12 @@ public async Task<IActionResult> GithubSignin(
             Logger.Error(error);
             throw new Exception(error);
         }
-        req.Headers.TryGetValue("Referer", out var _backEnd);
-        string backEnd = _backEnd.ToString() ?? req.GetDisplayUrl();
+        req.Headers.TryGetValue("Referer", out var _backend);
+        string backend = _backend.Count != 0 ? _backend.First() : req.GetDisplayUrl();
 
         string idToken = await _githubService.GetIdTokenAsync(
             authorization_code: code,
-            redirectUri: AuthenticationService.GetRedirectUri(backEnd, "api/signin-github"));
+            redirectUri: AuthenticationService.GetRedirectUri(backend, "api/signin-github"));
 
         // Treat it as an implicit flow-style URL so that my front-end can easily handle it with packages (angular-oauth2-oidc).
         return new RedirectResult($"{_frontEndUri}/pages/login-redirect#state={HttpUtility.UrlEncode(state)}&access_token={idToken}&token_type=Bearer&expires_in=3599&scope=email%20profile&authuser=0&prompt=none");
diff --git a/Services/Authentication/GithubService.cs b/Services/Authentication/GithubService.cs
index a1aed51..3b97940 100644
--- a/Services/Authentication/GithubService.cs
+++ b/Services/Authentication/GithubService.cs
@@ -62,7 +62,7 @@ public async Task<ClaimsPrincipal> GetUserInfoFromTokenAsync(string token)
 
         using var payload = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
         var identity = new ClaimsIdentity("github");
-        identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, payload.RootElement.GetProperty("id").GetString() ?? "", ClaimValueTypes.String));
+        identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, payload.RootElement.GetProperty("id").GetInt32().ToString(), ClaimValueTypes.Integer32));
         identity.AddClaim(new Claim(ClaimTypes.Name, payload.RootElement.GetProperty("login").GetString() ?? "", ClaimValueTypes.String));
         identity.AddClaim(new Claim(ClaimTypes.GivenName, payload.RootElement.GetProperty("name").GetString()?.Split(' ', StringSplitOptions.RemoveEmptyEntries).FirstOrDefault() ?? "", ClaimValueTypes.String));
         identity.AddClaim(new Claim(ClaimTypes.Surname, payload.RootElement.GetProperty("name").GetString()?.Split(' ', StringSplitOptions.RemoveEmptyEntries).LastOrDefault() ?? "", ClaimValueTypes.String));