This can be caused by verification of the Authenticode signature over the Internet. In case of problem with connecting to the verification server. Microsoft recommends to avoid the unnecessary startup cost associated with verifying the publisher signature unless your application executes on a computer with custom CAS policy, or is intending to satisfy demands for PublisherIdentityPermission in a partial-trust environment.
To avoid this verification, add the following code to the "app.config" file:
<configuration> 
     <runtime> 
           <generatepublisherevidence enabled="false" /> 
     </runtime> 
</configuration>

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