Hi no it seems quite random. I use an Edge browser on PC. Mainly I am just reading (so no audio), and try and click on a blue word and then sometimes the message comes up, and then the word stays blue. I click on ok on the error message, but then the next blue word I click on does the same. A page refresh sometimes helps or I just move to another lesson, and the problem goes away. Its not a disaster, but it ruins the flow of the lesson when it happens. I checked that it was not the internet connection dropping out.