ADMembership exception when trying to use SqlMembership and no connection to the AD

<div class="post-text" itemprop="description"> I am using 2 membership providers, sql provider and Active directory provider
I am switching between them in the run-time based on some logic, I check for the username and if found in the local accounts (sql provider) I just invoke the "AspNetSqlMembershipProvider" If not found there I would switch to "ADMembershipProvider" and search for him in the active directory
I am using AD account to connect to the active directory to authenticate users and retrieve users details
when I invoke "AspNetSqlMembershipProvider" and there is a problem in the active directory connection, an exception raised about this even I am not invoking the "ADMembershipProvider" at all
here is the exception
System.Configuration.ConfigurationErrorsException was unhandled b ...