Do you nat the traffic going over the vpn? If there is no nat, how is the other end going to know where to send the reply?
Either they need to have your internal ip range in their routing tables or you should nat the traffic.
the thing is, that i can ping my notebook pptp client, but no mikrotik pptp clients, so i suggest i have to add some special route on the mikrotiks clients?
192.168.212.115 is my smokeping server and i need to ping from there 10.0.0.7 so on the 10.0.0.7 mk should i add route 192.168.212.115/32 gw 10.0.0.1?
If you have control over the MT routers AND there is not ip range clash, you could simply add routes to all relevant networks to all MT routers. That would be the best approach not requiring any additional natting. It’s best to work with network ranges, so it will more for more than one pc/ip