You may want to try this steps.

1. Log on to the machine where the sql server instance resides.

2. Start SSMS. Use windows authentication (assuming your account have access to the server).

3. Right click the instance and choose properties.

4. Select Connections on the left pane.

5. Tick "Allow remote connections to this server". found on the right side.

6. Click ok button.

7. Close ssms and logoff to the server.

8. Access the sql instance again using ssms from a remote server.

Let me know if this works.