Error code 721

same here, connection error 721 since yesterday

Battlefront 2, Error code 721.

is actually a error code for the EA's servers.

can be DDoS attack or just bad server connection.

you can try this and see if it helps.

most of the times, it helps just do a full restart on your router.

Connection troubleshooting (ea.com)

Server issues on EA's side. Many on Steam are reporting widespread server issues at the moment, we just have to wait for them to fix it

I know my connectivity (PC) is good but the 721 error code does continually pop up with SW 2 Battlefront.

I found that persistence helps..... I keep trying to connect. It may take only one retry at worse 4 or 5 but eventually I have managed to get connected to the servers.