Hi, feixue.
According to the configuration of the hunt group, it can be known that the Waiting time for group connection (s) is set to 10, which means that the unanswered system will automatically release the call within 10s. However, the ringing time can be heard 3 times in 10s. Setting the Waiting time for group connection (s) to a long time can solve this problem. The recommended configuration is 60.
I hope I could help you.