We couldn't parse the input provided as a Date value.

This is a type conversion error but without looking at the power query steps it is difficult to tell you exactly what the solution will be. You could try to add a "Remove errors" at the end which will remove the erroneous rows but of course this won't be the ideal method since I am assuming you don't want to lose data. Also in my experience the data being displayed are only the first 1000 rows whereas the error might be in a row below so if you select "Column profiling based on the entire dataset" and use the drop down to try to scroll and see if you can identify something which doesn't look like a date. If none of these help then having a look at the problem via screenshot is probably the way to go.