Activity sharing disable

both my bro and I have Apple watch series 3 (Aluminium) curretly bought from the official apple site.

we're now trying to share the activity each other, my bro lives in Singapore and I live in South Korea.

I did every effort I can do based on the information discussed this forum such as iCloud re-sign-in, watch re-pairing and so on.

what happened is I sent invitation to my bro, he accepted it and he can see my activity.

but I don't. I can see my invitation is still waiting his acceptance. we tried this several days and never get improved at all. What are you guys going to recommend to do?

my i.O.S version is 11.2.5, same with my bro, quite new version,

my watch is also newest 4.2.3 and my bro is 4.2.