Hello,
Thanks for contacting us, and sorry for any inconvenience that might have been caused due to that.
Please make sure you’ve connected with the correct Google account on Rank Math.
If so, please try re-connecting your Google account with Rank Math by following the steps I’ve mentioned below, without skipping them.
#1 ~ Remove Rank Math’s access from Google
Please remove RankMath’s app from your Google apps permissions:
https://myaccount.google.com/permissions

#2 ~ Re-connect to regenerate auth token from Google
After that, reconnect the Google account again, to regenerate the auth token from Google, by going to WordPress Dashboard > Rank Math > General Settings > Analytics and configure the Search Console and Analytics settings again:

#3 ~ Grant all necessary permissions
Kindly check all necessary checkboxes to allow Rank Math to access some of the Google Services. Please check my screenshot below for reference:

#4 ~ Setup
Once the above process is done, please follow the URL below to setup you GSC account with Rank Math properly:
https://rankmath.com/kb/connect-your-google-account/#num-3-connect-to-search-console
Let us know how that goes. 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.