remove location path=""
Try this
<location path="Signup">
<system.web>
<authorization>
<allow users="*" />
</authorization>
</system.web>
</location>
<system.web>
<httpRuntime targetFramework="4.5" />
<compilation debug="true" targetFramework="4.5" />
<authentication mode="Forms">
<forms loginUrl="Login.aspx" timeout="2880" />
</authentication>
<authorization>
<deny users="?" />
</authorization>
<system.web>
I assume you have a Signup folder under the main folder and a login.aspx page in the main folder