1. The optical interface of the optical modem is faulty and the optical modem needs to be replaced;

2. The indoor pigtail fiber connector to the optical modem is loose and the plug connector can be restored;

3. Some indoor optical fibers are bent too much. Excessive bending of the optical fiber will affect the transmission of the optical signal in the optical fiber, as long as the optical fiber is straight;

4. If the outdoor optical fiber is broken or the optical interface in the machine room is faulty, a broadband fault report is required, and staff will come to troubleshoot after the fault report.