We would need more details to be able to help you on this matter.
Which OU Certifier ID file password did you loose ?
Is it the one you created specifically for the configuration of your SmartCloud Notes Hybrid environment, as described in the following documents ?
If so, did you forget the password before or after uploading it to the SmartCloud Notes servers, as described in the second document above ?
If it is not for this specific Hybrid-related OU Certifier ID file you lost the password, then I believe this would not be SmartCloud Notes specific, and you should be able to get some help from the usual support teams. It would more than likely take some more private exchanges to share confidential details