Hi @võ thị tuyết ngân,
Thank you for your reaching out and welcome to Microsoft Q&A!
From the error message you provided, could you please verify:
- The instance is running in SQL Server Configuration Manager
- SQL Server Browser is running in SQL Server Configuration Manager
- Try to connect to SQL Server with SSMS
- If the port number of the SQL Server Service is blocked by a firewall
In addition, we need more information to locate the cause of error accurately. Could you please post the detailed Application log in the [Window Log] to help us narrow down the issue?
Thanks for your understanding. Your time and cooperation are much valued by us. We are looking forward to hearing from you to assist further.
Best regards,
Lucy Chen
If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our Documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
https://docs.microsoft.com/en-us/answers/support/email-notifications