Hi @Hasan Sabbuba ,
Thanks for reaching out.
This is the expected behavior when the user hits ‘Cancel’ button Azure AD B2C will return an error response with Error Code -AADB2C90091 so that application can catch this error code and redirect to other page i.e signIn or signOut page.
The way to handle this error is to either catch them in your application or hide the cancel button using java script or CSS file.
Hope this will help.
Please remember to "Accept Answer" if answer helped you.