Hello @salihbora,
Thank you for reaching out,
Actually, it’s just a warning and it does not hurt or affect the performance of your website.
You can temporarily hide this message: https://ww.wp.xz.cn/support/topic/error-before-creating-new-post-after-updating-to-themes-latest-version/#:~:text=Please%20note%20that,wordpress/%23wp_debug.
However, the developer team has already been notified about this topic, and we will fix this warning in future updates.
For a temporary solution, you can do the following steps by using FTP/sFTP or your host file manager. Add this code: $gutenberg_css = ''; at line 50 here: /public_html/wp-content/themes/oceanwp/inc/third/class-gutenberg.php
Save all changes.
Hope it helps.
Best Regards
