KB486239: Login screen is empty or invalid after project security setting from MicroStrategy Web were modified to use another authentication mode

ISSUE:
When the user enters the login screen of web they encounter the following screen, or an empty screen or a message informing about an invalid login Mode.

CAUSE:
The user has modified the login mode to be another type inside preferences:

User does not have this item properly configured but this change has been forgotten about.
They also have the setting of override Project Login Modes disabled and at some point, they restarted the web server.
Because the admin page cannot override the project setting logging mode the current deployment becomes inaccessible displaying an invalid or empty login screen.
ACTION:
The following actions will be indicating how to restore the standard authentication.
To quickly restore the deployment to be accessible via Standard  authentication, the user you could follow 3 procedures:
 

1. If you have access to the admin page, then; check Override The project login screen once again:

In some cases, a restart of the web server is necessary.
 

1. If you have no access to the admin page you could add overrideProjectLoginModes=true inside the sys_defaults.properties located in /StrategySTD/WEB-INF/xml/ and then restart the web server

1. Lastly check the sys_defaults.properties for the following parameters: 

“enabledloginmode” and “ defaultloginmode” and set them equal to 1 (Standard authentication) and if parameters are not set, add them.
For example:
connectmode=auto
connectorWebBaseURL=https\://machine0000.Strategy.com\:8443/Communityonnectors/
showLoginPageAfterLogout=false
consumerWebBaseURL=https\://machine0000.Strategy.com\:8443/MicroStrategyLibrary/
enabledloginmode=1
defaultloginmode=1
Finally restart the web server for the changes to take effect and login with Standard authentication should now be successful.
Note: This procedure can be followed also for other authentication modes.