API error when trying to access IBM Quantum Computer using IBMQ API Token

Question

I'm trying to write a code so that if the token exists then it loads the account or else it asks the user for the API token. Below is the code for reference:

from qiskit import IBMQ
try:
    IBMQ.load_account()
except Exception as e:
    api_key = input("Enter IBMQ API Key")
    IBMQ.save_account(api_key, overwrite=True)
    IBMQ.load_account()

However, even after using the exception handling, still getting below errors:

RequestsApiError: '401 Client Error: Unauthorized for url: https://auth.quantum-computing.ibm.com/api/users/loginWithToken. Login failed., Error code: 3446.'

IBMQAccountCredentialsInvalidToken: 'Invalid IBM Quantum Experience token found: "" of type <class \'str\'>.'

Any work around this to resolve this issue?

Answer 1

The way I would do this is slight different:

from qiskit import IBMQ

api_key = None
for attempt in range(3):                                                # <- (1)
    try:                                                                # <- (3)
        if api_key:
            IBMQ.save_account(api_key, overwrite=True)
        else:
            IBMQ.load_account()
        break                                                           # <- (4)
    except Exception:
        api_key = input("Enter IBMQ API Key (attempt %s): " % attempt)  # <- (2)

This 3-time-loop (line (1), you can replace it for while True: if you prefer infinite looping over this) sets a variable api_key (line (2)) continuously asking for the key while something goes wrong (line (3)). The things that can go wrong are save_account and load_account. If nothing goes wrong (line (4)), then get out of the loop.