Hi, I've got exactly the same configuration than scheme 2 here:
Both sides have dynamic dsn address (no-ip). The other RUT is connected to the mobile network and the other end is connected to the cable network. So both ends have a public ip-address.
The connection worked well almost a year but after testing RUT with another operator's SIM card, also the old ipsec connection stopped working because I changed the configuration. I also upgated both routers to the newest firmware.
Seems that there is problem with routing, because the ping works to the routers' public ip-adress but not to the lan-addresses. The system log shows following errors:
Mon Sep 10 20:09:07 2018 daemon.info syslog: 07[NET] sending packet: from 46.132.xxx.xx to 78.27.xxx.xxx (372 bytes)
Mon Sep 10 20:09:08 2018 daemon.info syslog: 08[NET] received packet: from 78.27.xxx.xxx to 46.132.xxx.xx (60 bytes)
Mon Sep 10 20:09:08 2018 daemon.info syslog: 08[ENC] parsed QUICK_MODE request 2178071263 [ HASH ]
Mon Sep 10 20:09:08 2018 daemon.info syslog: 08[KNL] received netlink error: Network is unreachable (128)
Mon Sep 10 20:09:08 2018 daemon.info syslog: 08[KNL] unable to install source route for 192.168.1.1
I've tried every combination of IPSEC parameters but I allways get those network errors.