404 on the internet (wifi or mobile data) says "page not found". If it happens on a system like Google's Play servers, I'd suspect the local Play server (Google maintains many servers around the world for the same service). I've used play a few times already today (updated a few apps). About the only thing possible might be to try resetting your DNS servers. Use wifi, but set the address manually. (Long-press the connection, then check Advanced.) Use the same IP address it shows, but change the DNS addresses to 8.8.8.8 for the first one and 8.8.4.4 for the second one. Their DNS server should have the correct address for their Play server. (I use those addresses on all my devices, so maybe that's why I'[m not having any problems.)
I've tried changing the primary and secondary DNS for my wifi but it still gave me an error 404. I've also tried using an app (DNset) to change my DNs, but although I don't have the error, it still doesn't download.