CAP packets are encapsulated in ethernet frames and are treated by switch the same way as IP packets (encapsulated in ethernet frames). For CAP device to communicate with CAPsMAN in usual cases the connection has to be transparrent and playing with VLANs on all 3 devices doesn’t help if you don’t really know what you’re doing. You may want to go through this tutorial about how to configure VLANs on Mikrotik gear.
What we would need to see what’s in the way are full configs of all 3 devices (CAP device, switch, RB4011) and information about which ports are interconnected.