http://centraladmin:2020 has worked for weeks with no issues.
No updates or farm configuration changes have been made.
All services, app pools, web sites, and sql are running just fine.
All other web applications (that run on different wfe servers) are working just fine.
CA runs on the main APP server and the web site is started.
When you navigate to the site address (http://centraladmin:2020) it prompts you as if all was normal but then after entering your credentials it comes back
"The webpage cannot be found" HTTP 404
I've run the configuration wizard again and that did not fix the issue.