Cryptographic error on a SharePoint 2013 Provider Hosted App

Below mentioned is the error:

System.TypeInitializationException: The type initializer for 'ABABABA.TokenHelper' threw an exception. ---> System.Security.Cryptography.CryptographicException: Access denied. at System.Security.Cryptography.CryptographicException.ThrowCryptographicException(Int32 hr) at System.Security.Cryptography.X509Certificates.X509Utils._LoadCertFromFile(String fileName, IntPtr password, UInt32 dwFlags, Boolean persistKeySet, SafeCertContextHandle& pCertCtx) at System.Security.Cryptography.X509Certificates.X509Certificate.LoadCertificateFromFile(String fileName, Object password, X509KeyStorageFlags keyStorageFlags) at System.Security.Cryptography.X509Certificates.X509Certificate2..ctor(String fileName, String password)

We are pretty sure the App Pool account has access to the file and the path is correct. We have had a dozen number of people who checked these things out.

Please help out.

Thanks,

Aseem Sood