Error when using fetchById in Client Script

Error when using fetchById in Client Script

When using client script when creating page (onLoad), I suddenly getting error "Cannot read properties of undefined (reading 'Accounts')" when using: 
  1. var account_details = ZDK.Apps.CRM.Accounts.fetchById(account_id);
I'm getting this error whenever trying to fetch record by Id, although the id field is populated.
It used to work until just recently and suddenly does not.