Login Pages Fails to Load on Salesforce Experience Builder

Check for Custom Components

Even if no custom components are visible in the Page Editor, a hidden or misconfigured custom component may be preventing the login page from loading.
How to check:
Navigate to Setup > Digital Experiences > All Sites > Builder > Page Structure.
Under this setup, check if any component has a </> icon beside the Trash Can icon. This indicates a custom component. As an initial troubleshooting step, remove the custom component to see if the login page loads.

Check for Custom CSS

Custom CSS can sometimes interfere with the login page rendering.
How to check:
Navigate to Setup > Digital Experiences > All Sites > Builder > Theme > Drop-down arrow > Edit CSS.
If there is custom CSS, copy and paste it to a text editor, remove the CSS from Experience Builder, and check if the login page loads. Restore the custom CSS after testing.

Check for Custom Head Markup

Custom Head Markup scripts or stylesheets can cause the login page to fail to load.
How to check:
Navigate to Setup > Digital Experiences > All Sites > Builder > Settings > Advanced > Edit Head Markup.
If there is custom Head Markup, copy and paste it to a text editor, remove (or comment out) the markup from Experience Builder, and check if the login page loads. Restore the custom Head Markup after testing.