Some time Processing bar , confirmation message did not display while generating Invoice

Environment- Codemap
Company Name - For QA-City of Bellevue-Azure

Step:-
1.Login with SA
2.Navigate to Invoice Management >> Generate and View Invoices
3.Enter all mandatory details
4.Click on Generate Invoice

Actual - Application display few second processing bar and did not display confirmation message

Expected - It should display processing image still invoice is not generated