Error 401

Hi guys, great plugin!
But the last few weeks we are not getting and reviews. Today we were contacted by one of our customers, saying that there’s an error and he can’t send the review.
He goes through the steps, and on the last steps it gives and error 401. Here’s a screenshot: https://prnt.sc/m0rt2g
Please let me know what you think, as we are kind of depended on your plugin ??
Cheers
D