error on sending fax using FAXCOMEXLib on iis

Question

hi.
i am programming sending fax using FAXCOMEXLib.
when run it using visual studio, sending fax work correctly.

but when i publish source and want send fax using iis, show this error:

 Object reference not set to an instance of an object.

what permission must be applied in iis?


please help me. it is very important for me