Hey @ece! Thanks for your post.
Could you attempt a call through the test API in the Contacts v3 Documentation? I don’t know what exact request you are making, but I was able to successfully archive and create two contacts in postman with this endpoint.
These errors can sometimes be caused by a VPN or browser issue. Have you attempted these requests on different networks and browsers? If you still have trouble, please provide the request payload excluding any personal information or access tokens.
Best,
Kennedy