If embedded SIMs (eSIM) are the future, well have to walk on a rocky road to get there many EE subscribers are reporting that their Apple Watch Series 3 is failing to connect to the network. This seems to be an EE issue rather than something Apple messed up, but it hasnt been a smooth launch either way.
Users are typically faced with one of several errors including: activation failed and this account is not ready to use with Apple Watch. If youre experiencing issues activating your LTE-enabled Series 3 watch, you can dial 150 for help EE has trained personnel standing by.
Hit the Source link for more info. Note that it could take up to 2 hours for the LTE connection to actually be activated. If you see activation failed or another error, call EEs support.