Just installed RankMath & Got Error

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.

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/

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.

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.

Thank you, and we really look forward to helping you.

Hello,

Thank you for that additional information.

Please disable Rank Math temporarily by renaming the folder seo-by-rank-math in your website’s root directory – /wp-content/plugins/.

Upon further checking the error message, this issue might be due to your other plugin 301-redirects. After gaining access to your WordPress dashboard, could you try to deactivate that plugin and rename the folder seo-by-rank-math to its original filename, and see if the issue persists?

Thank you, and looking forward to your update.

Hello,

Thank you for following up.

In this case, it seems that the plugin might be using an old library CMB base on the error message you are getting.

If you still wanted to use that plugin, please contact the plugin author/developer to fix this issue or you can use the Rank Math redirect option instead of a separate plugin.

I hope that helps. Thank you, and looking forward to your update.