We had the same issue and solved it with the following steps:

1. Extract the ID from the ID Vault

2. Delete the ID from the Vault

3. Recertificate the exctracted ID

4. Switch to the ID and resync it with the ID Vault

Regards

Christian

Hi!

How can i "3. Recertificate the exctracted ID" ?

To recertify a user ID
Follow these steps to use the Administration Process to recertify a hierarchical ID that is about to expire.
  1.    To recertify a user ID, you must have:
Author with Create documents access and the UserModifier role, or Editor access to the IBM® Lotus® Domino® Directory
At least Author with Create documents access to the Certification Log (CERTLOG.NSF)
  2.    From the Domino Administrator, click the People & Groups tab.
  3.    Select the user to be recertified with the same certifier.
  4.    From the tools pane, select People - Recertify.
 

blah blah blah.

See 'Recertifying a user ID' in Admip help

BTW - if you're running an early release of 9.0.1, such as 9.0.1 before FP8, there are a number of vault issues that were fixed and pretty stable at 9.0.1FP8.

Thanks!

i running 9.0.1 FP7