Three weeks ago I reset my Apple Watch , and now it connects to my phone but I get error code 04 when I try to connect it to data. I’ve contacted 02 and they haven’t been very helpful to be honest, they once tried to reset the sim?? No luck. They promised someone would contact me within 5 days , they promised this every time I phoned because I wasn’t contacted, today someone from said they will send me an esim but I don’t see how that will make any difference as the Watch says no Sim No Connection. Can anyone offer a suggestion? Thanks.
Ask O2 to remove the watch from your account, then wait 24 hours before trying to reconnect it via the watch app on your phone.
The law of averages suggests you'll get someone useful eventually !