Reason: The web application cannot access EasyXLS.dll
If the web application does not have proper permissions, it cannot access the registered EasyXLS.dll.
Possible solution #1: Set permissions on EasyXLS.dll
The most suitable solution is to give permissions on the EasyXLS.dll that was registered as COM+ on the machine.
If the registration was through EasyXLS installer, the default location of EasyXLS.dll is "<EasyXLS install path>\COM+ version\DLL\EasyXLS.dll".
If EasyXLS.dll was moved and registered from a different location, then EasyXLS.dll must be searched at that location.
Right-click on EasyXLS.dll, choose Properties, Security tab:
Check if Everyone user is present. If it is not present, add Everyone user with full control or add the user used by the web application.
Possible solution #2: Set permissions on the web application
Another option is to increase the permissions for the web application.
Open Internet Information Services (IIS) Manager in Control Panel/Administrative Tools. Select Application Pools and the application pool associated with your web application.
Select Advanced Settings and check if Process Model/Identity is set to ApplicationPoolIdentity.
If so, change the Identity to LocalSystem:
If the application pool is used by multiple web applications, you might consider to create a new application pool only for the web application that uses EasyXLS.
Warning: Switching to LocalSystem is the easiest solution, but this decreases the security on the machine and it is not recommended for live environments. Best option is to run the web application under a Specific User with lower permissions and give permissions to that user according to Possible solution #1.
Possible reason #3: IIS Server and permissions on .NET components
The authenticating identity of the site has to match the identity of the application pool, otherwise IUSR user does not have enough permissions. If the site uses a "Specific user", switch to use "Application pool identity".
