Unexpected Application Error!

o.map is not a function

TypeError: o.map is not a function
    at https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:36575
    at f (https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:28320)
    at Generator.<anonymous> (https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:29657)
    at Generator.next (https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:28683)
    at v (https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:35332)
    at a (https://www.digitalbook.io/static/js/67.931358a0.chunk.js:2:35535)