What is wrong with my date field for this transform map?

[e_wilber]

On my transform, I am getting this error:

This field is set up as:

And my spreadsheet looks like: 

Why is my format wrong if it's dd-mm-yyyy in my column W and the date format in ServiceNow matches it?

[Pratiksha]

can you share how it looks like in stagging table?

[e_wilber]

This is what it looks like on my staging table: