Hey there,
RTMPS -> We did have some issues with RTMPS push input, however with 3.7 that should be resolved.. I'm unaware of RTMPS push output not working. We regularly test this against services that use RTMPs and are known to us. (like Facebook). However I don't think I've got any that use authentication as well. So that might be a problem. If you have a service or endpoint to test against I can verify that.
SSL + 3.7 -> I'm not quite sure what you're trying to say or what issue you're running into. Unless I'm mixing up abbreviations NPM to me is a javascript based package installer, so I'm not quite sure how or why you would want to use this to set up a HTTP(S) proxy and how this would work (or not work) in combination with MistServer. Could you perhaps explain that one a bit more? Happy to try and "fix" whatever worked for 3.0 but isn't for 3.7, but I'll need to understand what it is 😅
Best,Balder Vietor | Supreme tester