ASP.NET Forms Authentication issue in separate servers in separate networks

I have two applications with a single domain name (www.domain.com and test.domain.com). First one has been developed in .NET 2 and the other one with .NET 4.

I have configured Web.Config as these steps:

1. I've set the same machine key for both of them.
2. I've set the cookie name.
3. I've set the domain name to "domain.com开发者_运维技巧".
4. Also, I've set hard-coded cookie domain name to "domain.com" .

Everything was working fine when both of them were running on a single web server. Recently, I've been asked to move test.domain.com to another server. After moving, authentication ticket is not valid on the second server.

I tested both of them on a single server again and everything was working fine, but in two servers users can't access to test.domain.com. (Authentication Ticket is invalid)

Edited:

The second server is a virtual (VMWare) server. I don't have any problem in physical servers.

I checked the server's time to be synchronized. I also used Fiddler to see if the server does not get the auth ticket and their ticket is sent to the 2nd server.

Note: Servers are located in different networks and maybe proxy or firewall causes this (I've no idea)

Is there anything I missed?

Finally I've found it here:

http://weblogs.asp.net/scottgu/archive/2010/09/28/asp-net-security-update-now-available.aspx

One of ther server was not update, after installing the patch the issue solved!