vlookup not working in google sheets

I have a worksheet populated with a google form. The first column is populated with a default time stamp but the stamp comes in with date and time.

I am trying to run a simple vlookup based on the date, but I only want to use the date and not the time. The vlookup is not working because the time stamp is date and time and my lookup value is just the date. Even formatting the timestamp column to only show date does not work.

How do I resolve the issue or at the least change the default time stamp format?

That was the ticket. Thanks