Dear @nef
Like most users, it seems that you use mod_rewrite rules to remove index.php and journal path.
and there are double slashes in the link that @rcgillis added.
https://www.conjunctions-tjcp.com//announcement
So, you need to check your mod_rewrite rules (in .htaccess)
Perhaps, those posts might help you to identify the problem.
Regards,
Update: When I visit the journal that exist in the screenshot, it has published its first issue on 21th of May. Perhaps, you might have tried to use an existing journal path?