When you execute SOAMANAGER sometimes it may not load your internet browser windows and seems like it does not do anything. This will be related to an SAP GUI issue and I will show you how to confirm this and get around the problem. But first ensure you try executing SOAMANGER using the /O and /N command options to see if this fixes the issue:
The next step is to ensure the function module CALL_BROWSER works. To do this use transaction se37 to view the FM and then test it with a standard web site URL.
Execute tcode SE37, enter FM name as CALL_BROWSER and press test
Enter a website URL and press execute
If CALL_BROWSER works you can now debug SOAMANAGER and pinpoint the issue because depending on your GUI version it actually uses this function module to call the browser window.
Within here set a break-point and execute tcode SOAMANAGER again. You will then see if your SAP system calls the method call or the CALL_BROWSER function module. If it calls the method you need to debug again and at the point where it does the GUI check(CHECK_GUI_SUPPORT) change the return value so that it calls the function module. It should now work and provide you with the correct URL to SOAMANAGER
SOAMANAGER to setup SAP web service
Creating a SOAP (WSDL) web service within SAP
Test SAP HTTP connection ready for REST Web Service call
REST Web Service from SAP use getpostman to test first