How to force users to login into Salesforce through their IdP instead of through their My Domain login URL?
|Knowledge Article Number||000003761|
If we want to restrict users from logging in from login.salesforce.com and <company>.my.salesforce.com when using Federated Authentication (SAML), then we should follow the approach given below.
1) We should ensure that "My domain" is enabled for the Org.
At this point users accessing the My Domain login URL should be redirected to their IdP login URL.