My project works well (send e-mail) in local PC, but it can not when uploaded. I have checked SMTP port again and again, port 3535 is open. May the problem caused by config file? I think no. Appreciate all the help, thank you so much and hope to hear from you soon!

Description: The application attempted to perform an operation not allowed by the security policy.  To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Net.Mail.SmtpPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

Source Error:

Line 66:         SmtpClient client = new SmtpClient();
Line 67:         client.Credentials = new System.Net.NetworkCredential(SMTP_USERNAME, SMTP_PASSWORD);
Line 68:         client.Port = 3535;   //SMTP_PORT
Line 69:         client.Host = SMTP_HOST;
Line 70:         client.EnableSsl = ENABLE_SSL;

Source File: d:\hosting\clearpathadmin\contact-us.aspx.cs    Line: 68

Stack Trace:

[SecurityException: Request for the permission of type 'System.Net.Mail.SmtpPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
   System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
   System.Security.CodeAccessPermission.Demand() +59
   System.Net.Mail.SmtpClient.set_Port(Int32 value) +106
   stats_contact_us.SendMail() in d:\hosting\clearpathadmin\contact-us.aspx.cs:68
   stats_contact_us.btnSubmit_Click(Object sender, EventArgs e) in d:\hosting\clearpathadmin\contact-us.aspx.cs:48
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +105
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +107
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6953
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +154
   System.Web.UI.Page.ProcessRequest() +86
   System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +18
   System.Web.UI.Page.ProcessRequest(HttpContext context) +49
   ASP.contact_us_aspx.ProcessRequest(HttpContext context) in App_Web_zel1nich.0.cs:0
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +154
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64

Hi

 "Request for the permission of type 'System.Net.Mail.SmtpPermission" means you should have had unrestricted permissions, please check the security level for your websites and sets it to a unrestricted set of permissions.  To fix it, added this line to Web.Config for the web site:

 <trust level="Full" originUrl="" />

Hi Xiao Yong Dai

Thank you so much,  SMTPPermission may only need "Medium" trust level. But whatever, this error occured! Contact with hosting company, thay told me to modify my web.config but I don't know how. Can u or anyone help me? THANK U SO MUCH!

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: This configuration section cannot be used at this path.  This happens when the site administrator has locked access to this section using <location allowOverride="false"> from an inherited configuration file.

Source Error:

Line 20: 
Line 21: 
Line 22: 			<trust level="Full" originUrl="" />
Line 23: 
Line 24: 		<customErrors mode="Off"/>

Hi Xiao Yong Dai

Thank you so much,  SMTPPermission may only need "Medium" trust level. But whatever, this error occured! Contact with hosting company, thay told me to modify my web.config but I don't know how. Can u or anyone help me? THANK U SO MUCH!

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: This configuration section cannot be used at this path.  This happens when the site administrator has locked access to this section using <location allowOverride="false"> from an inherited configuration file.

Source Error:

Line 20: 
Line 21: 
Line 22: 			<trust level="Full" originUrl="" />
Line 23: 
Line 24: 		<customErrors mode="Off"/>

Hi mrdanh

Yes you're correct. In ASP.NET version 2.0, SmtpPermission is available at full, high, and medium trust levels. 

I'm afraid the hosting company used a custom trust (SMTPPermission is denied) and prevented you from override the trust level.

So, You'd better contact your ISP for this problem.

Please send me