i build l2tp + ipsec with guide from wiki, also i read many articles about that
so it works great with my windows10 laptop but i need it on my android device too, at first there was problem that i couldn`t connect to vpn but after reconfigur i have connected from android but after maximum 1 min, in ppp> active connections, my connection disappears and i lose connection , in ipsec> remote peers connection is steel on , and my android says that its on too
Do you have more than one device trying to setup L2TP from the same ISP?
IF so, there could be your problem. Due to a limitation in RouterOS you cannot setup more than one L2TP connection from the same source IP.
So when your ISP puts everyone behind NAT, it does not work. The results will be like what you experience.
maybe but when it happens only one device is connecting no more
but in future i think there will be some more devices who will need to connect to this vpn from android, can you make some advice what to do?
So the task is that i need some more secure vpn connection then pptp from outside to my office lan network, from pc and from smartphones too, there may be 2 or 3 smartphone maximum at same time
MikroTik really should fix this, but apparently they consider L2TP to be phased out anyway so not much is going on.
You can consider using IKE v2 instead.
There is also a workaround for this problem in a topic on this forum, but it is not something for beginners.