Debugging is not supported under current trust level settings.

Following is an email I received regarding SharePoint development. I thought you guys may benefit from the answer one day if you are in to SharePoint Development

Hi Gayan,

I have read your article on DevX about Sharepoint it was very helpful. I am new
to sharepoint I am running under a problem where I need to run an Asp.NET
application on the same server under which I am running Sharepoint portal
server, as u know U have to exclude the path if you will use any external
Asp.Net program. Well I did that but I am having error stating..

Server Error in '/Supresta' Application.

Debugging is not supported under current trust level settings.

Description: An unhandled exception occurred during the execution of the current
web request. Please review the stack trace for more information about the error
and where it originated in the code. Exception Details: System.Web.HttpException:
Debugging is not supported under current trust level settings.Source Error:

An unhandled exception was generated during the execution of the current web
request. Information regarding the origin and location of the exception can be
identified using the exception stack trace below.

Please advice me where is the error.

Best Regards

Attiq Khan

I believe you have already added your DLL and the pdb files to the SharePoint Server BIN directory. You need to make sure the web.config file of the SharePoint is updated as display below,
Change the line
<trust level=" WSS_Minimal" originUrl="" />
To
<trust level="Full" originUrl="" />
By default, the original trust level is “WSS_Minimal”. This will prevent developers from debugging and adding new application to the SharePoint Server.