Why am I unable to log in to Help Center in Safari or on iOS devices?
Users occasionally run into issues with logging into the Help Center on their iOS device or when using Safari. This is caused by the Prevent cross-site tracking setting, which blocks certain types of data from being preserved during the login redirection. Native authentication relies on cross-site tracking, so it needs to be disabled for users to be able to log in using Safari.
This setting is enabled by default and users need to manually disable it to fix the issue. To disable this setting, follow the instructions in this article from Apple's Help Center: Prevent cross-site tracking in Safari on Mac or Browse privately in Safari on iPhone.