Sorry, I didn't think of it! Here's a URL but I was having the problem with any story from this fandom & archive. I've made your suggested change, and it solves the first replace problem, thank you!, but I'm still not able to replace "archiveofourown.org" with AO3 - though I did also try escaping the "." since I had forgotten to do that, but it made no difference.
https://archiveofourown.org/works/14...pters/32639742