The other party's mobile phone has been talking.

What you want to ask is why the other party's mobile phone has been talking? The reason for this is the following：

1. The other party is talking to someone else, so you need to wait for the other party to finish the call before trying to contact.

2. The other party's mobile phone has a technical failure or network problem, which causes the system error to be displayed on the mobile phone. You can try to contact each other again later, or communicate with each other in other ways, such as sending text messages or using other communication applications.

3. The other party deliberately sets the mobile phone to an active state to avoid answering calls or communicating with others. In this case, respect each other's choices and try to communicate with each other in other ways.