Unable to put blocks on the sidebar of site's homepage

Hi. We are using OJS (PHP version 8.2.18). We are currently configuring a multi-journal site. You may visit the site https://journals.du.ac.bd/.
As you may have noticed, the right side of the homepage has reserved space for sidebar blocks.
However, we are not being able to put a ‘Make a Submission block’ block (or any custom block) in the sidebar of the site’s home. We could however put the block in the homepage of each individual journal (e.g. https://journals.du.ac.bd/index.php/afj).

Any suggestion on how to resolve the issue ?