Telethon: Reconnect problem

Hi, I reconnect to another dc and reconnection is done successfully (I have checked server address in client’s session) but when restart script this error is shown when client tries to connect.

[13:22:41.576/MainThread] WARNING: Read RPC error: (RPCError(...), 'The key is not registered in the system.')
Traceback (most recent call last):
  File "sample.py", line 110, in <module>
    channel_info = client.invoke(ResolveUsernameRequest(username))
  File "C:\installation-path\Python\Python35\site-packages\telethon\telegram_client.py", line 175, in invoke
    self.sender.receive(request, timeout)
  File "C:\installation-path\Python\Python35\site-packages\telethon\network\mtproto_sender.py", line 139, in receive
    request)
  File "installation-path\Python\Python35\Python\Python35\site-packages\telethon\network\mtproto_sender.py", line 217, in process_msg
    return self.handle_rpc_result(msg_id, sequence, reader, request)
  File "C:\installation-path\Python\Python35\Python\Python35\site-packages\telethon\network\mtproto_sender.py", line 350, in handle_rpc_result
    raise error
telethon.errors.RPCError: (RPCError(...), 'The key is not registered in the system.')