Hello. Please help. I have the following configuration:
Router: Hap AC 2
Hotspot: 2 * Cap AC

Wi-Fi is controlled by capsman running on a Hap AC 2. Capsman also manages wi-fi on itself.
4 ssids are used, each ssid uses its own vlan and subnet. The access points and the router are in their own management vlan. Version router OS 7.7 on all devices.
The problem is that printers connected via Wi-Fi are periodically inaccessible to users. It appears spontaneously. Sometimes everything works, sometimes it doesn't. At the same time, printers are always available by ping from the router itself. Connected to the same point in the same ssid where the printer is connected. Sometimes they are not available even when the client and printer are connected to the same access point. The client to client forwarding solution sometimes helps and sometimes doesn't. Maybe there is some direction how to fix the situation. Does it make sense to transfer printers to another ssid in another vlan? Maybe there are some options?

You may want to enable multicast helper on the wifi interface where your printer is connected to. It will make the AP send discovery things like ARP- and mDNS-requests as unicast to the individual connected devices instead of broadcasting them at basic rates.
At least for me, this helps too ensure wifi devices like printers are always reachable. However, depending on the type and number of wifi devices connected, this setting may cause other issues, like preventing power saving on mobile phones, so your mileage may vary.

Once you get multiple SSIDs and VLANs into the fray you need to set multicast helper to full. The poorly worded documentation alludes this.

https://help.mikrotik.com/docs/display/ ... agoverride

Good luck deciphering that but really yes, it means turn on multicast helper to full so broadcasts on a particular VLAN go to the right Wifi MAC/device.

Even without VLANs I have had trouble with printers being detected (as they use mDNS for service discovery) until the helper was enabled.