I have done some testing with Mikrotik hAP ac³, but L2TP connection remained stable.
Have you noticed, if there are any circumstances, such as increase in traffic, when the disconnects begin to occur?
Would it be possible for you to share the configuration settings of Mikrotik in a private message?
I would also like you to login to the RUTX14 router via SSH and enable additional logging. To achieve this, once logged in, execute the following command:
Remove # mark from debug option. Once done, press Esc, then enter :wq and press Enter.
Restart L2TP service with the command:
- /etc/init.d/xl2tpd restart
Wait some time, generate a new troubleshoot file and attach it as well.