tip: arthur merlin words>1000 sort:hits
Your app isn't working right now saying there's no internet even tho I can get on Google also I can't see it on the Google play store
I'm not Support but I know there is no official app for the AO3. I know several unofficial ones have been created, but to deal with any issues for them, you'd need to find and contact the app's creator because AO3 support has no control over any of them.
Last Edited Wed 23
adding to dizmo's comment:Please also be aware that when using one of those apps you should be cautious with entering your AO3 user ID and password (or updating your e-mail addess or any personal information): As dizmo said, none of those apps is from AO3 or the OTW or authorized by them, so by logging in to AO3 via one of those apps you would be giving your credentials to a stanger who has nothing to do with AO3/the OTW.
As others said, there is no official app for this site. Whatever you're trying use sounds pretty sus. Chances are that you're not finding it on Google Play because it could be a phishing app.