issue resolved by using 3rd part certificate, it looks like self-signed certificate isn't supported by Power Automate.
Microsoft graph API unable to run HTTP action api call using certificate based authentication

I am getting this error "BadRequest. Could not load the certificate private key. Please check the authentication certificate password is correct and try again." when I execute HTTP api call in Logic Apps / flow
3 answers
Sort by: Most helpful
-
-
Saurabh Sharma 17,366 Reputation points Microsoft Employee
2020-02-27T02:02:58.447+00:00 Are you using Client Certificate Authentication or Azure AD OAuth Authentication with a Certificate ? Please check if you are passing the parameter values with correct syntax to the outbound call. Refer to the documentation which describes the required properties you need to send while using client certificate authentication or Azure AD OAuth authentication.
Reference guide for trigger and action types in Azure Logic Apps is available here
-
Karl Briscoe 1 Reputation point
2021-01-20T14:29:38.97+00:00 If it helps anyone else: I had this same issue and after speaking with a Microsoft support member was given this resolution:
Certificates generated through the cert MMC or PowerShell will not work directly. To get them to work use openssl to convert them to a pem, then back to a pfx, like this:
openssl pkcs12 -in mycert.pfx -out mycert.pem
openssl pkcs12 -in mycert.pem -export -out mycert2.pfxThis mycert2.pfx file will work within Azure logic apps (once you've got the base64 string)
Strangely, if you import the mycert2.pfx file into the Certificates MMC, then export it again, it still works.