Hello,
Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.
If this is just happening to a single/specific post, assuming you are using the latest version of all the plugins and the themes (please update if not yet), it would seem like a conflict with one of the plugins or the theme you are using.
To determine that, please follow this troubleshooting guide:
https://rankmath.com/kb/check-plugin-conflicts/
Here is a video you can follow as well: https://www.youtube.com/watch?v=FcIWRhcUP2c
Only the site admin would know and your users won’t be affected by this troubleshooting.
If the issue persists, please edit the first post on this ticket and include your WordPress & FTP logins in the designated Sensitive Data section.
Please do take a complete backup of your website before sharing the information with us.

It is completely secure and only our support staff has access to that section. If you want, you can use the below plugin to generate a temporary login URL to your website and share that with us instead:
https://wordpress.org/plugins/temporary-login-without-password/
You can use the above plugin in conjunction with the WP Security Audit Log to monitor what changes our staff might make on your website (if any):
https://wordpress.org/plugins/wp-security-audit-log/
Please do take a complete backup of your website before sharing the information with us.
We really look forward to helping you.
Thank you.
Thanks, that seemed to work. I disabled my theme in troubleshooting mode, enabled a default WP theme, updated and saved the post using that theme, then switched back to my my preferred theme, now the RankMath dashboard also appears on that post as it should.
Hello,
The changes made in the troubleshoot mode do not affect the live website.
Could you please confirm if the Meta Box is appearing on the post after disabling the troubleshoot mode and when your preferred theme is active?
If not, then please check for the conflicting plugin/theme by following the guide shared by my colleague.
Looking forward to helping you.