Hi BellaHamilton-5865,
Welcome to Microsoft Q&A.
What the authentication are you using?
If you are using SQL Server login to connect to SQL Server, please login to the SQL server with windows authentication, then right-click the server name in the SSMS object Explorer-> Properties -> on the Security page, under Server authentication, please make sure to select “SQL Server and Windows Authentication Mode”.
If you are using windows login, please go to SQL server configuration manager to ensure named pipes and TCP/IP is enabled. And turn off the firewall and antivirus software in the computer.
Please also check the similar thread which might be helpful.
Best Regards,
Amelia
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