pptp interface, mppe negotiation.

 Hi!

I'm running UTM 9, up to date, home licence, and am trying to set up the PPOA/PPTP interface option to connect to a VPN provider.  This /almost/ works... but I'm seeing an mppe error causing the connection to abort :

2017:05:26-11:28:30 utm pppd-pppoa[29551]: pppd 2.4.6 started by (unknown), uid 0
2017:05:26-11:28:30 utm pppd-pppoa[29551]: Couldn't open pty slave /dev/pts/0: No such file or directory
2017:05:26-11:28:30 utm pppd-pppoa[29551]: using channel 70
2017:05:26-11:28:30 utm pppd-pppoa[29551]: Using interface ppp0
2017:05:26-11:28:30 utm pppd-pppoa[29551]: Connect: ppp0 <--> /dev/ttyp0
2017:05:26-11:28:31 utm pppd-pppoa[29551]: sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0x0> <magic 0xb3d3942d> <pcomp> <accomp>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [LCP ConfReq id=0x1 <mru 1396> <asyncmap 0x0> <auth chap MS-v2> <magic 0x77597a69> <pcomp> <accomp>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [LCP ConfAck id=0x1 <mru 1396> <asyncmap 0x0> <auth chap MS-v2> <magic 0x77597a69> <pcomp> <accomp>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [LCP ConfAck id=0x1 <mru 1492> <asyncmap 0x0> <magic 0xb3d3942d> <pcomp> <accomp>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [LCP EchoReq id=0x0 magic=0xb3d3942d]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [CHAP Challenge id=0x64 <8bf41547fa296a2649198aa065f1837a>, name = "pptpd"]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [CHAP Response id=0x64 <xxxx...xxxx>, name = "xxx@xxx"]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [LCP EchoRep id=0x0 magic=0x77597a69]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [CHAP Success id=0x64 "S=5D42E0934C167A69FAA0B02B6E0EDC09421A2062"]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: CHAP authentication succeeded
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [IPV6CP ConfReq id=0x1 <addr fe80::1106:4a53:b69f:4fbd>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [CCP ConfReq id=0x1 <mppe +H -M +S -L -D -C>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [CCP ConfRej id=0x1 <mppe +H -M +S -L -D -C>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [LCP TermReq id=0x2 "MPPE required but peer negotiation failed"]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: LCP terminated by peer (MPPE required but peer negotiation failed)
2017:05:26-11:28:32 utm pppd-pppoa[29551]: sent [LCP TermAck id=0x2]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: rcvd [CCP ConfRej id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
2017:05:26-11:28:32 utm pppd-pppoa[29551]: Discarded non-LCP packet when LCP not open
2017:05:26-11:28:32 utm pppd-pppoa[29551]: Script /usr/sbin/pptp-current 216.151.180.39 --nolaunchpppd finished (pid 29552), status = 0x0
2017:05:26-11:28:32 utm pppd-pppoa[29551]: Modem hangup
2017:05:26-11:28:32 utm pppd-pppoa[29551]: Connection terminated.
2017:05:26-11:28:32 utm pppd-pppoa[29551]: Exit.

Some digging would imply that it's related to this issue: http://pptpclient.sourceforge.net/howto-diagnosis.phtml#mppe_rbpnf 

Has the patch mentioned in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=294232  been applied to the version of pptpclient on the UTM? 

Has anybody got any suggestions?

Thanks.!