Membership.ValidateUser returns false

Hi!

I have 2 web applications and one membership database.if i create user in one application then it is validated in that application but not in the other application, MemberShipuser object is returned in both the application but the user cannot be validated against given username and password.

 

if i call GetPassword Method of user created on other application i.e. user.GetPassword() it is throwing an exception

"System.Security.Cryptography.CryptographicException: Padding is invalid and cannot be removed.
   at System.Security.Cryptography.RijndaelManagedTransform.DecryptData(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount, Byte[]& outputBuffer, Int32 outputOffset, PaddingMode paddingMode, Boolean fLast)
   at System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)
   at System.Security.Crypto ...