Although clearly this has been out there for some time, we weren't aware of the JWT requirements, so we have been trying in the last day to get this working for our client. We don't have our own RC account, and since it seems that the ability to send SMS has been removed, we can't try it on our own account. We are able to authenticate with JWT, just can't actually send an SMS message because the feature isn't available. We had the client create a new JWT application for production so that we wouldnt impact the existing password based application, but we can't even get that one to give an access token - we just get "Unauthorized for this grant type,Invalid Authorization header".
I've seen other posts suggesting that it can take some time, but it's been over 3 hours and we still can't get it to work. What other options might we have to troubleshoot this? If it helps, the clientid is aIQTZJnTatBbK49Tq5ioNd. Appreciate any tips or suggestions.