hi

i've created with a hap ac2 router a configuration with a 'home dual ap' quick set.
For internet I've an automatic address acquisition = 192.168.1.165 with gateway = 192.168.1.1
the local network is dhcp server with ip adress = 192.168.88..1
All work fine, i'e a lot of device connected for example 192.168.88.251
Now i would like from an address 192.168.1.x from a computer connected to my internet box (address = 192.168.1.25) to acces to the mikrotik local network. I'd like to connect for exemple 192.168.1.25 to 192.168.88.251.
I've tried to create a route between 192.168.1.x and 192.168.88.y but it doesn't work.
How i've to do ?

What exact route have you created? I assume you did that on your first router (with the internet which built the 1.XXX network).
You may have to create also a 'back' route on your 88.XXX network (on the ac2) that can route reply packets back to 1.XXX network. But the default 0.0.0.0/0 route that have to already exist with GW=192.168.1.1 would have to be sufficient.

You want to get into the local network (LAN) coming from WAN (via ethernet 0).
I assume your incoming connection (ICMP? UDP? TCP?) from xxx.1.x is probably blocked by RB Firewall.
Disable firewall to see if that is the issue (but be careful what you do )