Hello,
Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.
A bug made its way into yesterday’s update which is causing this error in some installations. The good news is that all hands are on deck patching this and you can expect an update to address this as soon as this weekend.
To fix this now, we are recommending downgrading to the previous version using this plugin: https://wordpress.org/plugins/wp-rollback/
Looking forward to helping you. Thank 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.