Fortigate Cloud API all devices endpoint not accessible anymore

[Tfromcube]

Good day! For monitoring purposes, we set up a custom integration with the Fortigate Cloud API. A couple of months ago, our custom integrations stopped working. Authentication still succeeds so it's not a credential/auth issue.

We noticed that the following endpoint does not return any data anymore: 

https://euapi.fortigate.forticloud.com/forticloudapi/v1/devices

 Instead we are hit with the following error:

{"error":"invalid_client","error_description":"Authentication failed","error_code":-1}

This error indicated invalid_client (we used fortigatecloud as per the docs). Even stranger is the fact that we can query the API enpoints for individual devices by specifying the gate's SN.

https://euapi.fortigate.forticloud.com/forticloudapi/v1/devices/FGT40FXXXXXX

This proves that my access_token is valid and can authenticate against the API endpoints (again: with client_id: fortigatecloud). The fact we get a valid response also confirms to me that it's not a network issue on our end.

Anyone have any similar issues/is able to replicate the issue in their env? Either this endpoint broke or has been changed. I have a FDN account and have full access to the endpoints. Thanks all for any suggestions.

[joshbergm]

Well... I don't think that this will solve your issue since it's a complete different software package but maybe worth a try

Client authentication failed since few months · Issue #37 · sendpulse/sendpulse-rest-api-php