We are installing the TMS 15.13 and database is on external SQL server with Windows based authentication. SQL Native client already installed , Windows Account login is verified successfully but still getting the error as login failed. How we can troubleshoot ?
Did you change the IIS application identity?
Please refer to the following document: Configure TMS to Use Windows Authentication for External SQL Server - Cisco
if you have already done the above, please share the SQL version that you have installed?
I'm no longer using TMS but I when I set this up the same way you are trying I recall a specific version of SQL native client was required. It was in the troubleshooting section of the install guide. Maybe uninstall and reinstall it.
Also make sure ports between TMS Windows server and external SQL are allowed to communicate. I also had that issue due to some data center requirements.