Setup Wizard doesn't work on Multisite

Hi RankMath team,

I posted a question on facebook:
https://www.facebook.com/groups/rankmathseopluginwordpress/325189121686754/?comment_id=325422474996752&notif_id=1552116734963605&notif_t=group_comment_mention

I checked cURL, everything is fine. I use Duplicator which uses cURL also and it works well. So I think the problem is not about cURL.

A short script what problem I have now:

Firstly, I installed RankMath on a fresh install Multisite page. After activing RankMath, it showed page “Sorry, you are not allowed to access this page.” I came back to the Dashboard and clicked Setup Wizard and once again, that page showed again. I tried many time to access but I couldn’t. I removed and reinstalled RankMath and the problem was still the same.

So I removed all files of the website, installed a new fresh WordPress. This time I didn’t use Multisite. I installed RankMath and it worked as charm without any problem. After setting up everything for RankMath, I actived Multisite and sadly the problem “Sorry, you are not allowed to access this page.” happened again. It happened anytime I active multisite and on all pages on the system.

So I think there is something happened between Multisite and RankMath.

Please spend some minute to check in my case.

Many thanks,
Nguyen