Hello,
Thank you for contacting Rank Math, and sorry for any inconvenience caused.
Please check if cron jobs are working on your website or not, you can use the WP-Crontrol plugin to check that.
In order to fetch the data correctly and consistently, you need to have the cronjobs working and enabled in your installation.
If the cron jobs are working, please reconnect the Analytics account, to regenerate the auth token from Google, by going to WordPress Dashboard > Rank Math > General Settings > Analytics and configure the Analytics settings:

Once you reconnect and configure the Analytics settings, the data fetch should start automatically.
Let us know if the data is not fetched.
We are here to help 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.