asp.net forms authentication logged out when logged into another instance

Question

I am doing some development on my local machine using VS 2010 and running my dev code in Cassini, I also have taken a copy of the same code and deployed it to c:\\mp and set

Answer 1

The issue is with the cookie, because the cookie keep the logged confirmation.

Changing the name of your cookie on web.config is probably solve your issue. So setup the name and the domain according to the two diferent logins, using 2 different cookie suffix names.