SMTP Relay auth not working

I think, there is the wrong expectation about this feature. 

Authenticated Relay expect an "live user" in the Live user tab and does not offer a SMTP transmission auth. 

I see... This could be an UTM expectation. I see what you say and you are right I can see from my authentication logs some of the VPN SSL authenticated but my user that are not using VPN cannot authenticated. 

So where is the SMTP transmission auth gone ? There are nothing like Email proxy looking like UTM email proxy and be so different at the end.

Like mentioned before. XG needs an "Live User". 

SMTP Transmission auth is something else. 

https://en.wikipedia.org/wiki/SMTP_Authentication

This is not implemented in the MTA of XG. 

(And to be honest, i did not like this option on UTM either - Most of the time, it could block your users on AD). 

For which reason do you need a Authentication relay? 

I quite understand you. I have never had problem with auth relay on UTM but I do not use AD.

All the SMTP traffic works well except for my clients outside sending emails from the WAN and trying to authenticate. I am sorry to not understand fully your concept of live user although it seems attractive. How to make them live users ?

So basically a live user is a user which is authenticated against XG.

STAS, SATC, SSO Client, NTLM, Captive Portal can authenticate against XG in LAN.

And nearly all VPN Clients authenticate against XG as well. 

Would recommend to use SSL VPN or IPsec VPN Remote access for your users and use the SMTP Relay authentication in this one. 

Works fine for me. 

I have a lot of small clients in many companies, it seems to me like a lot of work to install VPN SSL and reconfigure every account of emails to pass through the VPN... In practice I would prefer something more simple.

Can i ask, for which purpose they should send mails through your gateway? But to be honest, i think, this is not possible in XG like on UTM. 

Those people have email accounts behind the XG.

I have so two choices : either they are on VPN or unauthentified. 

I work as a MSP and I have clients I do not even see for whom I offer email account, so you can understand how this is difficult for me to add VPN SSL (although this is easy) for everyone.

Or start to deploy some kind of active sync (Office365 / Exchange). 

Seems like your needs would fit in active sync: https://en.wikipedia.org/wiki/ActiveSync