OJS pop up menu "accept submission" didn't work

I have a problem with our journal website. When I click the “accept submission” button, there is no pop-up that leads to the next step (attached screenshot). This problem never happened before. Any help would be greatly appreciated.

Dwi Setiawan
Problem OJS

Hi @ijop,

The version of OJS that you’re using is no longer supported by PKP. I recommend that you upgrade to the newest version of OJS, as it is possible that your issue will be resolved by upgrading. However, other community members may wish to offer assistance.

Upgrading instructions are available in the PKP Administrator’s Guide.

Information about the latest version of OJS can be found on the PKP Website

You may also want to check your PHP error logs to see if there is an indication of what is occurring, but it is possible that this issue may be fixed by upgrading your OJS instance.

PKP Team