Vlookup changed validated cell value in macro

I have a worksheet containing a cell (say A1) that has a validated list of times (data/validation/list) where the cells in the list contain times in 8 minute increments. The user can select cell A1 and manually select any of the validated times from the list.
A vlookup formula on this worksheet uses the content of cell A1 to look for this time in another section of the worksheet. When the time is selected manually, the vlookup formula works properly.

As part of a macro, the macro will change the time in cell A1. I do this in the macro by selecting and copying the desired time from the validation list and pasting it into A1. Cell A1 does change to the new value, however the vlookup formula that uses A1 shows a result of #N/A. If I manually change the time, it again works. I am looking for a way to have the macro change this cell to another time and for the vlookup formula to work as it should. Any suggestions?

Did you populate your val-list by entering values in the source box manually, or, are you using a range of cells?

Check that your dropdown list has no spaces .

Somewhere on your sheet, select an unused cell and enter the formula =A1; format the cell as number. Back in A1 select a value from the dropdown list.

Observe that the value in the test cell is a decimal greater than 0.0 and less than 1.0; if otherwise, then the list may have untimely characters somewhere.