With multiple bridges likely one of the issues discussed here https://help.mikrotik.com/docs/display/ROS/Layer2+misconfiguration, recommended practice is a single VLAN-aware bridge, there is a good primer here http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
As ever without seeing your existing setup it is impossible to say exactly what is incorrect, copy the result of /export hide-sensitive from a terminal window, paste in a code block (the icon in the forum post).