Unexpected Application Error!

Cannot read properties of undefined (reading 'push')

TypeError: Cannot read properties of undefined (reading 'push')
    at https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:36584
    at f (https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:28320)
    at Generator.<anonymous> (https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:29657)
    at Generator.next (https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:28683)
    at v (https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:35332)
    at a (https://www.digitalbook.io/static/js/67.2a1cdc02.chunk.js:2:35535)