Invalid argument error

Hello,

Thank you for contacting Rank Math and sorry for any inconvenience caused.

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.

Hello,

We are super happy that your issue is resolved. If you have any other questions in the future, know that we are here to help you.

If you don’t mind me asking, could you please leave us a review (if you haven’t already) on https://wordpress.org/support/plugin/seo-by-rank-math/reviews/#new-post about your overall experience with Rank Math? We appreciate your time and patience.

If you do have another question in the future, please feel free to create a new forum topic, and it will be our pleasure to assist you again.

Thank you.