I think the proper question would be how to obtain a token from ADFS, since the one I obtained is most likely from IFS IDP (according to OAuth Invalid Signature | IFS Community and dsj23 website IFS Authentication flow with OAuth and OpenID Connect – DSJ's Blog (dsj23.me))

Finally i was able to solve the issue, i was authenticating by IFS DB identity provider, but I should authenticate by ADFS. Once I obtain a token from ADFS i was able to authorize requests.

Hello. I’m having the exact same problem. I’ve used https://pdomain]/openid-connect-provider/idp/token to get the token and since it gave that error, I tried with https://login.microsoftonline.com/ntenant_ID]/oauth2/token and still didn’t work.

Can you share how you managed it?

Thanks

Hello

It depends how identity manager is configured in IFS.

In our case it’s ADFS (on-premise), not Azure AD.

I had to authorize the /token request with Basic method (includes a user which is IFS application ID - client id native - defined in ADFS, no password) and put in a body (www-form-urlencoded) 4 key-value pairs:

“grant_type” = “password”

“resource” = api://<INSTANCE_NAME>

“username” = IFS account directory_id

“password” = IFS account password

Additionally, added a request header: "Content-Type": "application/x-www-form-urlencoded"

Please, refer to below docs page for further explanation: