Here is my topology
Internal domain: inside.local (Two DCs)
DMZ Domain: outside.local (Two DCs)
Inside.local have a Web Application used by the local employees (Application is named WebApp)
Outside.local, have a database that WebApp uses, its a C# running on IIS on Windows 2012
one-way trust relation, outside.local trust authentication request from inside.local
WebApp needs to connect to the database in the DMZ, but users are getting the following error message.
Error message: Login failed. The login is from an untrusted domain and cannot be used with Integrated authentication.
I try to use ODBC from WebApp Server to connect to the SQL Server in the and I got the same error message.
Note that this issue is not persistent, users may fail in login for about 1 minutes, and then it work fine and they can login and work fine for another 10 minutes, and so on..
I check the authentication protocol and its using NTLM
Any idea on why this may happense