Help Please Account.Create() results in an exception in DotNet.

When I try to create a new user with the following code
await _account.Create(userId: "unique()", email: email, password: password);

It hit an exception which says System.Collections.Generic.KeyNotFoundException: 'The given key 'expired' was not present in the dictionary.'

There is no dictionary on my side. It has to be Appwrite internal issue. Please help.
Account gets created but no User object is returned.