Thank you for reaching out to Atlassian Community!
Just for us to better understand and help you with this issue, we would like to know more details about the issue you are facing.
Is it showing an error when you click on "Export"? If so, can you share with us a screenshot of the error?
Are you the only user facing this issue?
Please, let us know more details so we can follow the same steps here to confirm what is preventing the Export option to work.