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API response different on two different servers

Occasional Participant

API response different on two different servers

Hi there,


We have connected to the API and made a simple call to retrieve the names of the email lists in our account.


For this we have passed an Appkey, our constant contact username and a constant contact password.


We have exactly the same PHP code on two different servers, yet on one server a list of our email lists is returned and on another the array is empty.


I have been racking my brains to figure out how this is possible.  We are sending two identical calls to your API and getting two completely different responses, the only difference being the origin of the request.  To clarify, both scripts authenticate successfully and run the same API command - but get different responses!


Can you let me know how this is possible?   It's been bugging me all day and I can't see any resolution to this from our end.


Thanks in advance,



Hello Paul,


I'd like to reach out to you via email so we can exchange some information needed to troubleshoot our end of the requests. I'll send you a private message.



Mark Coleman
Support Engineer
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