I'm in the US and it works for me. There's a few things you can check:
- Coinos settings-> integration then go to the part Nostr that's where you import your npub
- Nostr just add coinos email/account info to your nostr profile.
You may have already don't this, but it can't hurt to double check. Sometimes I check my settings when I zap someone, I just hold the zap icon for longer.