.net Error : an internal certificate chaining error

Private Shared Function sign(ByVal input() As Byte, ByVal certificate As X509Certificate2) As Byte()
       'what is signed
       Dim content As ContentInfo = New ContentInfo(input)
       'who signs
       Dim signer As CmsSigner = New CmsSigner(certificate)
       ' represents a signed message
       Dim signedMessage As SignedCms = New SignedCms(content)
       'Sign the message.
       signedMessage.ComputeSignature(signer)
       'Serialize the signed message.
       Return signedMessage.Encode()
   End Function
   Private Shared Function encrypt(ByVal cert As X509Certificate2, ByVal input() As Byte) As Byte()
       'what is encrypted
       Dim content As ContentInfo = New ContentInfo(input)
       'represents an encrypted message
       Dim envelopedMessage As EnvelopedCms = New EnvelopedCms(content)
       'who can decrypt
       Dim recipient As CmsRecipient = New CmsRecipient(SubjectIdentifierType.SubjectKeyIdentifier, cert)
       'Encrypt the message.
       envelopedMessage.Encrypt(recipient)
       'Serialize the message.
       Return envelopedMessage.Encode()
   End Function
   Public Shared Function Signature(ByVal filename As String, ByVal certiID As Int32)
       'Getting the File Bytes
       Dim fileByte() As Byte = System.IO.File.ReadAllBytes(filename)
       'Getting The certificate
       Dim ds As System.Data.DataSet = GetCertificate(certiID)
       Dim byt() As Byte = New bal_MstCertificate().getcertificate(certiID).Tables(0).Rows(0)("CertCertificate")
       Dim pass As String = New bal_MstCertificate().getcertificate(certiID).Tables(0).Rows(0)("certPassWord")
       Dim myCertificate As X509Certificate2 = New X509Certificate2(byt, pass)
       'Signning the Data
       Dim signeddata() As Byte = sign(fileByte, myCertificate)
       Return encrypt(myCertificate, signeddata)
   End Function