SYMPTOMS
In Strategy Web Admin it is not possible to select different authentication mode if SAML is enabled as all other options are grayed out. This can be verified by going to the Web Administration page - Intelligence Server - Default properties - Login as shown in the screenshot below:

ACTION
As soon as SAML authentication is enabled for Strategy Web, other authentication modes are disabled. To allow access through other authentication modes, a second Web deployment will need to be created.
If users would like to use SAML and other authentication method at the same time it is necessary to create two different applications in the same web server or different and then enable Standard for example on one and SSO on the other. It is not possible to create a copy of the existing Virtual Directory because it is already enabled with SAML. It is necessary to create a new installation and create a new application in the Web Server so it has a different URL for where other authentication method desired can be enabled.
KB441157