If you can open the HAN2X web interface, the device is connected to the IP network. Continue with the Modbus-specific checks:

1. Use the current HAN2X IP address and the Modbus TCP port configured under Settings. The default port is 502.
2. Confirm that the client uses the configured Modbus unit or slave address.
3. Check whether the client expects zero-based register offsets or 4xxxx reference numbers.
4. As a basic read test, request meter power from holding registers 40001–40002. The value spans two 16-bit registers and is represented as a 32-bit integer; confirm byte and word order in the current manual.

If the test fails, record the exact request, unit address, exception or timeout, and HAN2X firmware version.