PHP SDK: currentUserEmail is not getting saved. There is no useridentifier in oauthtokens record

PHP SDK: currentUserEmail is not getting saved. There is no useridentifier in oauthtokens record

I have the PHP SDK set up and working... mostly. I've found the problem shows itself in the SDK when the response comes back from the generateAccessToken() method. The ZohoOAuthTokens instance does not have a userEmailId value. Also, when the SDK saves the tokens to the oauthtokens table, the useridentifier field is empty (but all the other values are there). I have traced the empty email field to the API response from the getUserEmailIdFromIAM() method in the ZohoOAuthClient class (In my files it's on line 157 of ZohoOAuthClient.php), which gets called in the generateAccessToken() method. getUserEmailIdFromIAM() makes a request to get user info and for some reason comes back with an error that ultimately gets 'translated' into null as the JSON response is processed. My question is, why is it happening and how do I fix this? This seems to be the last step in the process for getting our app configured. Thanks