Your original formula will only work if E4 is containing the name of an existing sheet. What you are trying can only make sense if the other cells in column E possibly getting referenced also contain the names of existing sheets.
Did you realise that?
The first “enhanced” formula you show us will try to interpret E as a reference (name). If you rectify it replacing E with “E” it will pass E followed by the digits of a row number, then a dot and I56. There will not be a valid sheet name. Thus no valid reference. Error indicator #REF!
The second try will also not pass a sheet name, and as a whole no valid address.
What you seem to be intending should be done by =INDIRECT(INDIRECT(“E”&ROW())&".I56") . (I don’t need the silly single apostrophes because I always use syntactycally clean sheet names.)
My Advice: Dont play with nested INDIRECTions. They are not in every case easily analised.
Don’t use sheet names except those made from one letter followed by a sequence of letters and/or digits. No spaces, no special characters! You are rewarded the omission of single apostrophes in connection with sheet names.
You should get a first working result if you simply fill down your original formula dragging the “fill handle” of the cell containing it. (The little square bottom right!)