If you encounter an issue where Visual Studio 2013 will not license itself or allow you to sign in, you need to follow these steps. The issue appears to be that the TLS version (v1.0) in VS2013 is no longer supported by MS so it cannot connect to the MS server(s) to license itself. The fix identified in the link below fixed the issue:

https://learn.microsoft.com/en-us/answers/questions/804062/unable-to-login-to-visual-studios-2013-upgrade-5

1. Open a "Windows PowerShell" command prompt as an adminstrator
   
   
2. Copy, paste, & run the following command:
   
   New-ItemProperty -path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -name 'SchUseStrongCrypto' -value '1' -PropertyType 'DWord' -Force | Out-Null
   
   
3. Re-run Visual Studio 2013