exception from hresult 0x800a03ec code example
Example: exception from hresult: 0x80131040
Finally found the answer!! Go to References --> right cilck on dll file that causing the problem --> select the properties --> check the version --> match the version in properties to web config
<dependentAssembly>
<assemblyIdentity name="YourDllFile" publicKeyToken="2780ccd10d57b246" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-YourDllFileVersion" newVersion="YourDllFileVersion" />
</dependentAssembly>