When I lost recv , I can't send any message anymore!

[KenyesLai]

Holle:
my code:
def SendBack(data):
msg = can.Message(arbitration_id=0x000601, data = data, extended_id=False)
bus.send(msg)
bus.flush_tx_buffer()
time.sleep(0.001)
try:
Ans = str(bus.recv(timeout=1.0))
except:
print("Error")
return(None)
if(len(Ans) > 10):
return("success")
else:
return(None)
My question is when it lost recv then i cant send any new message.
it can't send any data and any response.
I need to restart Raspberry Pi then CAN bus will be normal.
Please help me to fix this question.
Thank you