
Solved
Qualtrics - Mailinglist contacts API
I am trying to create Contract using Create contacts API but getting error of "Invalid mailinglistId."
https://api.qualtrics.com/reference/create-recipient-contact
I have got the MalilingListID by list-mailing-lists
!

Best answer by TomG
Double check your mailing list id under My Account/Qualtrics IDs. Also, make sure the account for the token you are using has access to the list.
BTW, it works for me:
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