Circular Reference error

Hello,

  I have a table that lists the ticket id and the creation date for the tcikets that came into our help desk.

TicketNumber   DateOpened

5-312                 1/14/21

3-dws                 12/28/20

w-32r                  1/13/21

I created a Date table using Calendarauto(). I have formatted both dates to be mm/dd/yy. I am now trying to link the date field in the Date table to the DateOpened in the Ticket table.  I keep getting a circular reference error and do not understand why.

Here is the error I get:

Eventually, I want to create a few measures in my Ticket table to count the number of tickets created each day, month and year.

I appreciate any help.

Cheers,

Peter