Sometimes, Vegas Pro gets stuck as a background process in the Task Manager especially with Windows 11. If this is causing the problem in your case, open the Task Manager (Ctrl+Alt+Del) and End Process for any Vegas Process listing under Background Processes - then try opening Vegas Pro again.
I opened the Task Manager, but there was no running VEGAS PRO app there. I cannot open still VEGAS PRO 19.0 . I should have not updated it because now I cannot use the app