When a user dials an extension number, the phone rings only once and is disconnected.
Step 1 Connect a maximum of two extensions to one line to ensure that an extension number is shared by only two extensions.
Step 2 If the fault persists, contact Huawei technical support engineers.
Three or more than three extensions share the extension number, so electrical signals are unstable. The called side constantly reports unhooking, hangup, and unknown messages, which causes the failure to set up the call.