Error 401 Unauthorized on accessing WebAPI externally (SOAP UI or a!httpQuery)

Question

Good Day Everyone, 
 We have created a sample GET WebAPI(ex:Hello World) in Appian. We hit the resultant URL and we get a proper message in a new tab of the same browser. 
 
 Now we try to hit the same WebAPI through SoapUI, we are facing Error 401 Unauthorized . 
 When trying a!httpQuery also, we face the same 401 error. 
 
 Note: 
 
 We are working on Appian 17.1 with WebLogic.(cannot be upgraded) 
 We are working on Banking domain and requires Intranet to access the same. 
 Basic Authorization with preemptive option is given in SoapUI. 
 We are using a new basic user with 'Viewer' security for the WebAPI. 
 Have provided accurate credentials in the 'Third-Party Credentials' (when testing a!httpQuery)in Admin Console page. 
 
 Please let us know your thoughts on the same. Thanks in advance.

Aadith · Accepted Answer

*****RESOLVED***** ANALYSIS -On checking the SoapUI logs, we found the message 'requires authentication with realm weblogic' -SoapUI sends a POST request to the application server with basic authentication headers, however WebLogic requires any POST request with basic authentication to be validated. -Thus, it strips the authentication headers before sending it to Appian. Appian will then receive a request without authentication details and returns Error 401 Unauthorized. SOLUTION -We created a new user with the same credentials in both Appian and Weblogic. -We hit the same WebAPI again and it was successful. -This solved the issue for both our GET and POST APIs. REFERENCE This post helped us: https://community.appian.com/support/w/kb/254/kb-1029-401-unauthorized-error-when-running-the-deployment-automation-manager-in-the-command-line?pi1605=100