The problem is that the current security policy does not allow processing theassemblies required for the proper application work. To solve this, log in toPlesk, goto Server > ASP.NET. In the Code Access Security section select FullCAS trust level. Then, log in to SmarterMail (SmarterStats) and activate it. After that,go back to Plesk > Server > Components Management and set SM (SS) as default.Now, the server-wide CAS trust level can be turned to its previous state.