IOS: how to debug kSecTrustResultRecoverableTrustFailure

Now I have read quite a few posts and sources but could not find a definite answer.

I am getting kSecTrustResultRecoverableTrustFailure in my SecTrustEvaluate () call and I would like to figure out why this is the case (i.e. I want to figure out where exactly the trust chain validation is checked and why). on OSX there seems to be some related function called SecTrustGetResult, but now it's deprecated even on OSX

How can I find out where the check is completed? I am fine with using the private API as I only use this during debugging to understand what exactly is going on internally.

thank