Sharepoint - 'Search list' is not working for classic pages as in Modern pages

Hello All,

    I am newly working in sharepoint. I got a problem when searching in the list in site.

Case 1 : I have display form as default modern page.When i search a word it is working fine.(please refer screenshot)

Case 2: I have display form as customized aspx page. In this case I am not getting the search task done.when i search a word it displays the custom display form name. for e.g how can isearch 'corn' here 😞 .Please help me. Thanks in advance.

case 2: