I just ran into this issue and found that @magic-code's response was correct, but if is not working for you or taking you to app configuration, here is what you gonna do:
1- In App Store Connect, click the "Apps" text link in the very top navigation bar.
2- Find your offending app in the list (I had just one so it was easy)
3- Is there a red notification bubble in the top-right corner of the icon?
4- If so, right-click directly on that red bubble and open the link in a new tab and BOOM, you are taken to Apple's Resolution Center so you can check the message from the review team.
Regards,
Julio D.