Hey experts please help me.

initially my site is in classic asp and i am trying to convert some part of my site is in asp.net. for authentication in both technologies first i create session in classic asp then by posting form to asp.net page i create session in asp.net also. day one and day two both technologies are working fine but after some time they hanged my server. asp.net pages hanged permanently, after this my web server do not response. I am confused what the issue here ?

Please help me. Thanks in advance