Why is the RDP or VNC connection not connecting or dropping on the OVPN network?

Question

Computer networks

The network looks like this:
My Network -> pfsense ->(ovpn 192.168.16.1)-> (Internet)<-Watchguard<-kerio<-(ovpn 192.168.16.2)<-pfsense<-The network in a foreign
OVPN branch was raised, there are routes , the traffic to walk to my network from the remote branch is to walk through pfsense.
At a remote branch there is a Watchguard on which there are 2 WAN and LAN interfaces, from LAN it goes to kerio where there are also 2 interfaces - LAN1 (WAN) is connected to Watchguard and LAN2 for the local network. inside the network pfsense in client mode is connected to my network. The connection does not break, BUT
1. Any VNC or RDP connection is not connected the first time or is disconnected after about half a minute.
2. The strangest thing is that if a user launches an OVPN client from a PC, there is a different connection principle, but it will be quietly let into the network and it will work without glitches by connecting to a terminal server on my network.
3. Can these problems be related to the fact that another VPN server already exists on the same ovpn server in my network and they have the same sharedkey?
4. Perhaps for the stable operation of the network, you need to allow some ports or networks additionally, but I seem to have already done this?
5. To forward the port (8080) on a remote network to pfsense, the port must first be forwarded from Watchguard to kerio? and then from another interface with Kerio to Pfsens' ip address on port 8080?? Or is it done in some other way?
Thank you for your help.