Originally Posted by
supine
Are you using at least one of those special characters but no other special characters?
I think it's a check that you are not using "invalid" characters for their definition of invalid.
My first attempt used exactly one of characters of the ones in the screenshot. (&) My next attempt was to add an additional one also from the ones shown (=) so that I now had two. On my third attempt, I tried using the Euro symbol which didn’t satisfy the special character requirement either. I tried a few more like a tilda and the degree symbol without any luck.