ZHC4661 point-to-point communication was fine when first set up, but after two days it cannot communicate

Q: After setting up ZHC4661 point-to-point communication, it was working fine initially, but after two days of use, it could not communicate.

A: There are two scenarios:

1. First, rule out device issues by connecting two 485 tools to check if communication is possible.

2. The group network ID and password might be too simple and conflict with other customers’ settings (or there might be an issue with the sensor).