VPN, synology and pihole

Hi,
this is my first post. I’m new in mikrotik.
I have Synology NAS with pihole container. I can configure my hAP ac^2 to redirect subnet to pihole.
I have also VPN on my synology. I can’t redirect VPN clients to pihole and to mikrotik router config.
I have static IP and I want to use full time VPN on android devices, but if I inside Mikrotik wifi, I can’t connect to VPN.
My config:
hAP ac^2: 192.168.1.1
Synology NAS with VPN and pihole: 192.168.1.109
VPN: 192.168.3.xxx

Please help.
Thanks in advance