I am using the V2 .Net dll and I will get an unauthorized error several times in a row and if I wait a couple of minutes I can retrieve and send data and then after a while it will revert back to returning an authentication 401 error for a while and then ultimately it will begin to work again
I can see that the api key and key are correct and that the url is formed properly
Is this a server issue or does it have to do with the status of our account?
Thank you for reaching out to Constant Contact API Developer Support.
The likely cause of your issue is that you are going over your calls per second rate limit. Our standard API access limit is 10,000 calls per day and 4 calls per second. If you make more than 4 calls per second, any additional calls will return with a 401 error until after 1 second after the first call was attempted.
Please let me know if you have any other questions!
Tier II API Support Engineer