Problem creating a clustered column chart to count...

Hi I'm still new to power bi and I have an issue creating a clustered column chart with 2 columns on the x-axis. I want to create a clustered column chart that counts the number of tickets created and resolved per month. I have a data set that contains a ticket reference number, the creation date and resolution date. When I add the creation date and resolution date to the X-axis only one column of data is displayed. I have tried switching off the concatenate option on the x-axis. Creation date and resolution date are both formatted as date type.: date thanks