You may have experienced that you cannot access your WAS installation anymore for whatever reason. If you are sure that you haven’t changed the credentials or something like that, there’s still a way to fix it.
I tried to inspect the services.msc on Windows. You can see there the WebSphere Application Server service. If its startup type is Automatic, change it to Manual. Then restart the machine. Start the deployment manager or server (depends on your environment) manually. Based on my experience, this should be okay now. If WAS is inaccessible again, change the startup type to Automatic and then restart the machine.
If you still cannot login, there must be some problem with your WAS configuration.
If anyone know the exact solution, please comment! 😀