Мой собеседник не получает от меня сообщения, но в то же время я от него сообщения получаю! В чём проблема, и как это исправить?
My conversation partner isn’t receiving messages from me, but at the same time, I’m receiving messages from them! What’s the problem, and how can I fix it?
Are you on your conversation partner’s blocklist? (accidentally).
Are you using different Chatmail servers? One server might be blocked. Many publicly-listed Chatmail servers are blocked in some countries. You could both try making another Chatmail account.
If that does not help, it could be useful to know more about your setup: What clients are you using? How did you add contacts?