Hi @hypwoman,
Thank you for your reply.
We can’t predict anything from the error message that you have shared as it is not descriptive.
Could you please share us the page URL where you are using the custom sidebar so that we can troubleshoot it?
Can you please try enabling WP_DEBUG mode? To do this, just go to wp-config.php include this:
define('WP_DEBUG',true);
You might already have a line for WP_DEBUG, so just make sure it’s set to true.
For information on this, checkout this wpmu.org article.
Let me know what more error information if any you are getting!
This can also be plugin or theme conflict issue that you are using, to resolve it could you please try troubleshooting the issue as described by @david in his previous reply?
Regards,
WPMU DEV