When inserting rows (Copy, Insert, Shift rows up/down) cell references may get messed up. Better way is to copy whole row, and then use Insert Copied Rows.

When originally the same formula was same for whole row, then the way to get table to work again is to find a row where formula(s) are OK, select cell(s), and drag up/down for rest of rows. Or correct manually the formula(s) in topmost row, and then copy down.

When the formulas were different for different rows, and you can't restore the file, or messing formulas up was done many days ago, you are out of luck and you have to create formulas anew.