Get 401 error when trying the sample code for


Get 401 error when trying the sample code for

I downloaded the sample code for for "Campaign sample forms" from the following page:

I tried to click on the link on the default.aspx page for "Listing all email campaigns" and I got the error (401) Unauthorized.

The reason I tried this in the first place is that I am trying to create some campaign programmatically and I could not because of the same problem.

So I need help on passing the authentication.

Sincerely Yours,

Hui Li


Regular Participant


In most cases, 401 errors are a result of an improperly formatted login. Your application will need to construct a HTTP Username from a concatenation of your API User Key, the "%" character and the Constant Contact customer's UserName. This information is passed with Constant Contact Customer's Password.


Please ensure the username you are passing is formatted as follows, where the string of letters preceding the % is your API key:




Andrew T

Support Engineer, Constant Contact

Developer Portal

View API documentation, code samples, get your API key.

Visit Page