"Error received from peer ipv4:127.0.0.1:50051"

[ILScience]

I want repetition iisy_sw/simple_example/decision_tree.
When I active dataplan successful ,and I use "./mycontroller.py" to install P4 program on s1,there comes a error:

> gRPC Error: (UNKNOWN)
> [./mycontroller.py:274]

Then，I add "print(e)" in function printGrpcError(e) which located in mycontroller.py,it prints the error details:

<_InactiveRpcError of RPC that terminated with:
	status = StatusCode.UNKNOWN
	details = ""
	debug_error_string = "{"created":"@1684120670.242352265","description":"Error received from peer ipv4:127.0.0.1:50051","file":"src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"","grpc_status":2}"
>
gRPC Error: (UNKNOWN)
[./mycontroller.py:274]
time to load the tables: 0.06884455680847168

[ILScience]

I have already stuck here for a week,please help me!!