Hello there,
We’re happy to hear from you and assist you with your issue.
However, before we proceed, we need to verify your account. It seems that you are using the Rank Math PRO plugin, but you have posted your query in the Free forum. This forum is only for users of the free version of Rank Math. To get support for the PRO version, you need to provide us with your receipt from FastSpring.com, our payment processor. Please forward your receipt to us so we can locate your account and confirm your purchase.
That said, the warning you’re seeing indicates that there is a problem with one of the schemas on your site. To fix this issue, you need to check if you are using any custom schema for your site. If you are using any custom schema, try deleting it and adding it back again. Make sure that you fill in all the required fields and options correctly when creating or editing your schema.
We hope this explains the situation and how to resolve it. Please let us know if you have any questions or concerns.
Cheers!
Hello Great,
We use the basic version of the plugin on the staging and the live site.
I installed RankMath v1.0.115 (while the current PRO version is v3.0.36)
There is nothing to verify.
The problem is that updating a website to PHP8.0 and PHP8.1 throws the following error:
Warning: Undefined array key “@id” in –PATH– /plugins/seo-by-rank-math/includes/modules/schema/class-frontend.php on line 252
I wonder how safe is updating the website to PHP8.0 or higher with the current RankMath version.
Hello,
Is there a specific page where you are getting this warning or is it visible sitewide? The issue seems to be related to a Schema that has the incorrect value for the @id field. If you allow us, we can check this on your site. If you are comfortable with it, please edit the first post on this ticket and include your WordPress 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/
Also, the account you have used is a Free account. Since you have PRO installed on your site, you should have a PRO account. Can you please share the email address of your PRO account so we can merge your accounts?
We really look forward to helping you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.