Hi all,
maybe someone will shed some light on my issue.
I am taking over an already configured site with multiple mikrotiks. Currently the setup is very straight forward. They have the remote sites connect to the main site via PPTP client / server. There are also some VPN users (also PPTP) that connect to the main site, but manage to see the remote sites.

My issue is as follows. I started to change some site from PPTP to IP and also GRE tunnels but now the people who connect via VPN to the main site do not manage to see the remote sites.
Any help is highly appreciated.