BSP Page not found

Question

I created a BSP application, created the SICF entry, and have been running the application for months.  All of a sudden I am getting a page cannot be found error.  It's like it can't find the initial page. 
When I go into an application that IS working, and I look at the url, I see something like this:
https://www.mysite.com/ss(bD1lbiZjPTEwMA==)/selection.htm?sap_client=100
The SICF application alias is /ss, and the initial page in the BSP application is selection.htm.  This works fine.
When I go into the application that is NOT working, this is the url:
https://www.mysite.com/ss(bD1lbiZjPTEwMA==)/?sap_client=100
It looks like it is not recognizing what the initial page is.  No change have been made to the application for a month, so I don't know why this started happening all of a sudden.

Answer 1

We have our own extranet site that we are running these from.   The BSP application has an initial page, and the sicf was used to create an alias for the bsp application.
One thing I noticed that i had wrong in my original message, the application that works looks like this:
https://www.mysite.com/ss(bD1lbiZjPTEwMA==)/selection.htm?sap_client=100
The one that doesn't work looks like this:
https://www.mysite.com/ss?sap_client=100
The whole "(bD1lbiZjPTEwMA==)/selection.htm" is missing.