Hittade följande i machine.config
<!--
Using a location directive with a missing path attribute
scopes the configuration to the entire machine. If used in
conjunction with allowOverride="false", it can be used to
prevent configuration from being altered on the machine
Administrators that want to restrict permissions granted to
web applications should change the default Trust level and ensure
that overrides are not allowed
-->
<location allowOverride="true">
<system.web>
<securityPolicy>
<trustLevel name="Full" policyFile="internal"/>
<trustLevel name="High" policyFile="web_hightrust.config"/>
<trustLevel name="Medium" policyFile="web_mediumtrust.config"/>
<trustLevel name="Low" policyFile="web_lowtrust.config"/>
<trustLevel name="Minimal" policyFile="web_minimaltrust.config"/>
</securityPolicy>
<!-- level="[Full|High|Medium|Low|Minimal]" -->
<trust level="Full" originUrl=""/>
</system.web>
</location>
Det bör då gå att lägga in <trust level=""> i din web.config.