Have you pasted wrong output results?

[yu8muraka3]

When trying to launch the chat client

Now let's do the same in our second empty terminal, but with account address 2 as argument (the contract address remains the same):

cd
cd workshop_code/code
python user.py 0x86817fbb2715c45d70163ba9de0b7af9c90f6282 0xc590c4d665805458171411ac442b1c8b291f32f5

You see, the second parameter is different.

Output:

Using TensorFlow backend.
--------------------------------------------------------------------------------
client software: EthereumJS TestRPC/v3.0.3/ethereum-js
block: 1
address: 0x0d56bafa9c8181199e99956a3f67eb937a47ce80

--------------------------------------------------------------------------------
found contract on blockchain!
--------------------------------------------------------------------------------
starting chat command line...
>> 

Is the address wrong? Correct address is "0xc590c4d665805458171411ac442b1c8b291f32f5", isn't it?

Are there any similar mistakes even further downwards?
Please check.