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Requesting help for invalid grant mystery

Brand Influencer
0 Votes


We've been running our code for months. We refresh our token every 6 hours automatically with

oauth2/default/v1/token   grant_type='refresh_token'

Once in an while, something like once a week, we will get a return code of 400 with the error message 

'invalid grant: the refresh token is invalid or expired'.   Then we have to go in and do the Auth by hand to get things working again. 

I've set up logging to make sure we are passing in the token that we previously had received. 

Is it possible for you to look at your logs (I have the time for when it first failed in the last episode), and do you have any suggestions on what I might look for?

Thank you

Brand Influencer
0 Votes

Hello! Is the any way we can get support trying to understand our problem?  

We basically have to be on alert to go in and re-auth at any time.  This is unworkable because we have to get in touch with the person who has the login to the account every time, which seems to be at least once a week. 

Again, works for most of the time. What are we missing? 

This is for long-time customers of Constant Contact with a substantial account.  Thank you so much.

0 Votes

Hello TinaI37,


Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.


It looks like we've already followed up with you directly via email, but I wanted to close the loop here as well. If you haven't received our reply, please let us know via email at, and reference case number 31231986.


Please have a look and let us know if you have any other questions!



Courtney E.
Tier II API Support Engineer

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