Hey there @bvisnjic,
hope you’re doing good today! 🙂
Are you trying to change sidebar for the archive category page, like http://yourdomain.com/category/uncategorized/?

I just tried that in a clean installation using TwentySeventeen theme and it’s working good.
This may be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.
If you can install plugins, install “Health Check”: https://ww.wp.xz.cn/plugins/health-check/ On the troubleshooting tab, you can click the button to disable all plugins and change the theme for you, while you’re still logged in, without affecting normal visitors to your site.
Warm regards,
Dimitris
I’m trying to change the sidebar on the post category page. Theme support tells me that the problem is with the plugin because CPO Allegiant theme supports it.
Also I disabled all plugins but sidebar still not showing
Hey @bvisnjic,
Hope you’re well.
Did you try also changing the theme? When you change the theme to WordPress defaults is sidebars working correctly?
I can’t try that theme pro version because of it’s paid theme but as far as I can see they are giving lite version as a free. So I tried the plugin with a lite version of the theme and looks like all working correctly.
First I enabled default sidebar to be replaceable;

Then I set the custom sidebar location settings like this;

Then when I check the front side it looks like working;

If your settings different, can you tell me which steps I should try to replicate? If this is only can replicate with pro version, can you ask your theme author to provide more information about the problem?
Cheers,
Oguz
Hello @bvisnjic,
it’s been a while since we’ve heard back from you, so I mark this topic as resolved. Feel free to reply back here, if more assistance is required and we can re-open it and continue troubleshooting. 🙂
Warm regards,
Dimitris