Active Customer Accounts not apprearing in Customer Page

Hi,

We have few active customer accounts which are not appearing in Customers page.

When we navigate to customers from CUSTOMERS-->CUSTOMERS and provide the account number then it says no data found irrespective of customer type and customer status.

But when we navigate from COLLECTIONS-->CUSTOMER ACCOUNTS and provide the account number in search screen it gives the data and when clicked on Customers option it opens the Customer page. We are wondering if it can get the data from Collections why the customers are not visible from Customers ?

I have checked if there are any page personalizations ,there are no personalizations .