In these instances, you should try and browse to REST (above) and then ensure your SQL instance is on and not in recovery or single-user mode.
This error is GlobalSearch uses 401s regularly as part of it's security and authentication protocol. It's very common to see 401s accompanied by 200s in Fiddler. However, a 401 is not ALWAYS benign and can be an indication of some malfunctioning component. Checking the error log for 401 errors will help tease out the actual problems from the normal operating procedure of the application. This error can be found in both the Smart Search error log as well as in the browser if you attempt to access a page from the restproxy or web services (GetSmart website). It indicates that the server refused the authentication attempt provided.
401 - Unauthorized: "Access is denied due to invalid credentials. You do not have permission to view this directory or page using the credentials that you supplied.
This can also be found in database connection calls where a username and password is provided in a DB connection string and it’s invalid.
Causes and Solutions:
|SPN issues are name resolution issues. These can be caused when a server's name and IP address have issues resolving. An easy resolution here would be to change the configuration files to use machine name instead of IP address or vice versa. Or use the setspn command to update the spn settings.|
|SSL bug in windows||There is a bug in windows when using SSL that may cause a 401.1 unauthorized. Follow the first method listed here to resolve the issue by adding the FQDN into the registry|
|Bad Connection String||The user passed through a connection string does not have proper permissions to a database. If you're using a connection string with explicit security, ensure the user being passed has access to the database specified.|
*SPN = Server Principle Name