Edge works OK on my test machine.
What does the error message say?
This website could not be found.
Error Code: INET_E_RESOURCE_NOT_FOUND
Is that even after refreshing?
By default, the help server only starts the first time you push F1 (or use the menu item etc.) after launching Opus, so if you use a bookmark in the browser it may not work until then.
In my home computer test normal, There may be my office computer system Problems.