Windows cannot connect to MacbookPro

It had been working but suddenly when I tried to connect by the IP address, a login screen came up.  Even though I entered the correct user name and password, I couldn't connect to the Mac computer.

Try either or both steps:

• Go to the Sharing on my MacbookPro, click "Options...", deselect the user account (and provide the password) then select the user account again (enter the password one more time).  
• Go to the Sharing on my MacbookPro, click "Options...",  disable the sharing (uncheck "Share files and folders using SMB", click "Done") and then enable it again.