Thank you for reporting the error in the new update, we will fix that soon.
As for the robots.txt error, I can see that the robots.txt on your site is working correctly. I don’t see any issue that could be causing the error you see. It might be related to some kind of cache, or it is a temporary issue on Google’s side. Nonetheless, I’ve made a small change in the robots.txt, through the editor available in Rank Math. Please try testing it again. If it is still not working, please wait for a few days, the issue should get resolved by itself.
Yes, I am actually searching for an answer for a long time and when I realised that robots.txt I switched. I love your plugin and I wanna use it so I can get it back if you want to check the issue yourself.