Added error handling (unauthorized) from okta
Added error handling (unauthorized) from okta

This must be done before trying to get the user,
otherwise the app yields an 400 error:
```
oauth2: cannot fetch token: 400 Bad Request
Response: {"error":"invalid_grant","error_description":"The authorization code is invalid or has expired."}
```

bnfinet/lasso,bnfinet/lasso