Data (citizen service number) not known to ZK

Hello everyone,

I have not been able to log in to Mijnzilverenkruis. I receive a notification that my social security number (BSN) is not known to ZK. 

I never had any problems with DigiD, I am able to log in at all sites. So the problem really isn't with the DigiD. 

Does anyone else have the same problem?

Andrei