Trying to use Indirect and offset in a data validation

[TamirBasin]

Hi,
When I use inside a data validation (list) the expression: Offset('Sheet1'!$E$1,0,0,COUNTA('Sheet1'!E:E),1) I get the correct list.
I also have that expression as a text in the cell A1.
When I write the expression in the data validation (list) =INDIRECT(A1) I get an error and no list is populated.

What should I do?

Thank you,
Tamir