Customer portal not showing error message on incorrect login

Summary

Customer portal not showing error message on incorrect login

Steps to Reproduce

1. In Service Desk project, add new customer
2. In separate browser window, open Customer portal page (<base_URL>/jira7121/servicedesk)
3. Try to log in using wrong password or username

Expected Results

Jira should display wrong credentials error message in browser.

Actual Results

Jira doesn't display wrong credentials message, the loading wheel keeps spinning. Thus, there is no warning that something is wrong.
Following gets displayed in the browser developer console in attempt to add an error message:

Workaround

None.