my auth_token is expiring again and again

i am able to successfully generate auth_code and the access_token.

but when i use this access_token it say

{'code': -16, 'message': 'Could not authenticate the user', 's': 'error'}

and then when i again try to generate access_token it say

{'s': 'error', 'code': -413, 'message': 'Your auth code has expired. Please generate a new auth code'}

i am using python code provided in sample fyers python repository