diff --git a/GmailTokenManager.cs b/GmailTokenManager.cs
index 1ce2cef..ecd9bbc 100644
--- a/GmailTokenManager.cs
+++ b/GmailTokenManager.cs
@@ -6,26 +6,42 @@ using System.Threading.Tasks;
 
 public static class GmailTokenManager
 {
+    //public static async Task<string> ObtenerAccessTokenAsync(GmailConfig config)
+    //{
+    //    var stream = new MemoryStream(config.ClientSecret);
+
+    //    var credencial = await GoogleWebAuthorizationBroker.AuthorizeAsync(
+    //      GoogleClientSecrets.FromStream(stream).Secrets,
+    //      new[] { "https://mail.google.com/" },
+    //      config.Usuario,
+    //      CancellationToken.None,
+    //      new FileDataStore(config.TokenFolder, true)
+    //  );
+
+    //    return await credencial.GetAccessTokenForRequestAsync();
+    //}
+    private static readonly SemaphoreSlim _tokenSemaphore = new SemaphoreSlim(1, 1);
+
     public static async Task<string> ObtenerAccessTokenAsync(GmailConfig config)
     {
-        //var stream = new FileStream(config.ClientSecretPath, FileMode.Open, FileAccess.Read);
         var stream = new MemoryStream(config.ClientSecret);
 
-        //var credencial = await GoogleWebAuthorizationBroker.AuthorizeAsync(
-        //    GoogleClientSecrets.FromStream(stream).Secrets,
-        //    new[] { "https://www.googleapis.com/auth/gmail.send" },
-        //    config.Usuario,
-        //    CancellationToken.None,
-        //    new FileDataStore(config.TokenFolder, true)
-        //);
-        var credencial = await GoogleWebAuthorizationBroker.AuthorizeAsync(
-          GoogleClientSecrets.FromStream(stream).Secrets,
-          new[] { "https://mail.google.com/" },
-          config.Usuario,
-          CancellationToken.None,
-          new FileDataStore(config.TokenFolder, true)
-      );
+        await _tokenSemaphore.WaitAsync();
+        try
+        {
+            var credencial = await GoogleWebAuthorizationBroker.AuthorizeAsync(
+                GoogleClientSecrets.FromStream(stream).Secrets,
+                new[] { "https://mail.google.com/" },
+                config.Usuario,
+                CancellationToken.None,
+                new FileDataStore(config.TokenFolder, true)
+            );
 
-        return await credencial.GetAccessTokenForRequestAsync();
+            return await credencial.GetAccessTokenForRequestAsync();
+        }
+        finally
+        {
+            _tokenSemaphore.Release();
+        }
     }
 }
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