Hi!
Clicking “Cornerstone” in the WP sidebar, leads to this:
**Warning** : Cannot modify header information - headers already sent by (output started at /home/customer/www/*/public_html/wp-admin/includes/template.php:2546) in **/home/customer/www/*/public_html/wp-includes/pluggable.php** on line **1421**
Not sure if it was caught already. 
@Misho, I cannot replicate this even with WP_DEBUG on. Perhaps this was a side-effect of something addressed in Beta 3, which has just been released.
Cheers!
All right. I have it in Beta 3 as well, but I noticed that other testing sites don’t have it. This site is specific for the fact that it was recently upgraded from X and it is being redesigned right now.
Other thing is that I upgraded to PHP 8.2 to see how it it holds on the testing site. That works great and it isn’t the reason for this error.
@Misho, gotcha. Sounds like something potentially related to that install. Keep us updated if you find anything else out that could point us in a direction, but as of this time I am unable to replicate on any local environments, even after testing upgrades.
Thanks!
Still struggling with this one.
I switched to a default theme and that allowed me to go to the plugins page. There I deactivated all plugins and switched back to Pro Beta 3.
The plugins page still has this type of error, for each of the plugins:
**Warning** : Undefined array key "advanced-custom-fields-pro" in **/home/customer/www/*/public_html/wp-content/themes/pro/framework/legacy/functions/updates/class-tgm-plugin-activation.php** on line **1828**
**Warning** : Undefined array key "advanced-custom-fields-pro" in **/home/customer/www/*/public_html/wp-content/themes/pro/framework/legacy/functions/updates/class-tgm-plugin-activation.php** on line **1915**
So the only different thing I see is that this was an X site, recently switched to Pro. Child theme is not active.
I have combined the information here with another thread where a user is experiencing an issue opening Cornerstone from the sidebar. Thanks!
Just FYI - I am experiencing this as well on an upgrade from 5.1.5 > V6Beta 3. Also was getting that same message from the cornerstone topbar (WP top bar) on occasion too. Happy to provide access if desired.
@DoncoMarketing, I believe the error you’re experiencing here should be addressed in the next release, so no need for credentials at this time, but thank you!
