SUM does not sum

Hi all,

I have a calculated value (calculated in power query, set as decimale value) and it shows the current values per row. Each row is unique.

However, when I sum that same value with the sum option (see printscreens below), it remains blank for some rows. Can anyone help me out? In the end I want to use the summarized value only but it does not show the correct amount and I think it is because of this.

The table with both values:

Settings of the first column set to "do not summarize":

Settings of the second column set to sum:

Many thanks,

Anne