Power Platform Community Forum Thread Details

Hi everyone,

I'm hoping someone has run into this before.

I'm integrating Power Automate Cloud with ADP API Central using the Premium HTTP connector and Client Certificate (mTLS) authentication.

Here's what's happening:

✅ OAuth request to https://accounts.adp.com/auth/oauth/v2/token succeeds using the client certificate.

✅ Access token is returned and stored in a variable.

❌ Every subsequent request to https://api.adp.com fails with:

401 Unauthorized

Request did not provide the required two-way TLS certificate.

I've tested:

/hr/v2/workers/{associateOID}

/core/v1/event-notification-messages

Both return the same error.

Things we've already verified:

The PFX is valid.
The private key exists.
The password is correct.
The same PFX works successfully in Postman for both OAuth and API requests.
The Power Automate HTTP action is configured with the same PFX and password on every request.
The run history shows the HTTP action includes the client certificate configuration, but ADP still reports that no client certificate was presented.

Has anyone successfully connected Power Automate Cloud directly to ADP API Central (or another third-party API requiring mTLS) using the HTTP connector? I'm also opening support cases with Microsoft and ADP, but I'd love to know if anyone has encountered this or found a workaround. Thanks!

Categories:

Connector development