I've installed Tia Portal Pro V16 on Windows 10 Pro 21H1 but when i want to simulate the project the error which accrued in :

please tell me what is the problem and what can i do to solve this problem without changing the windows.

Hello Yz.Mohsen,

the reason of this case could be the update of Windows 10.After a function update of Windows 10 it might happen that Windows 10 does not start the SQL database automatically. Reconfigure the Autostart of the service to clear the problem.

See also the information of the FAQ:

How do you ensure that the Microsoft SQL server starts automatically after a function update of Windows 10?

https://support.industry.siemens.com/cs/ww/en/view/109765539