Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to this issue.
Please follow the steps below to see if it works for you:
1. Delete RankMath’s app from here:
https://myaccount.google.com/permissions

2. Re-create tables by clicking WP Dashboard > Rank Math > Status & Tools > Database Tools and click the Re-create database Table button.

3. Reconnect the account inside Rank Math by clicking here and ensure that you approve all the permission notices that show up:
WP Dashboard >> Rank Math >> General Settings >> Analytics tab, and click the Reconnect link

Allow all the permissions on the next screen.

4. Let the process complete, which might take around 30 minutes.
5. Now head over to WP Dashboard > Rank Math > Status & Tools > Database Tools and click the Rebuild Index for Analytics button.

6. Please check if the data shows up here:
/wp-admin/admin.php?page=rank-math-analytics#/

If that does not help, please paste the data from here:
WP Dashboard > Rank Math > Status & Tools > System Status and click the Copy System Info to Clipboard button

Please note that the Index Status tab only works with URL-prefix properties in Google Search Console. These are the properties that have the full URL of your website, including the protocol (http or https) and the subdomain (www or non-www). For example, https://www.example.com is a URL-prefix property.
Domain properties are the ones that only have the domain name of your website, without the protocol or the subdomain. For example, example.com is a domain property. Rank Math has limited support for domain properties and cannot display the Index Status data for them.

Let us know how this goes.
Thank you.