Login page removed from the dynamics 365 Portla Add-On

Hello,
1- When I try to access the  Login page in My Portal (8.2.x.x) 
I get an Error message says  he cannot found the Login Page.
When I search in CRM I cannot find the Login page in  the web pages Area (and I think i was never their) !!

2- Is their a way to enable tracing for errors to see the exception Errors? 

Thanks