VMware KB: User Name and Password fields does not appear on the vRealize Automation login page.

This problem is between the vRealize Automation 6.2 Client integration plug-in and recent versions of Firefox.

As a workaround, you may be able to move the horizontal scroll bar, causing the screen to be redrawn, thus revealing the username and password input boxes.

Internet Explorer 11 appears to be pretty well behaved and the latest versions of Chrome also work well, though the Flash components may be old.