My RPI is connected to one of my routers and get its local IP.
When I am connected to another router, I cannot access HA through its IP.
How i can solve this?
You’ll want to create a static route between the two routers.
I cannot find how I can do it. Maybe you can help me?
Sure! I just need to know what kind of routers are you using? The process to setup a static route is dependent on the brand of router and firmware it’s running.
http://screenshots.portforward.com/routers/VTech/NB403/LAN_Configuration_Edit.htm describes how to setup a static route. I couldn’t find much info on the Xiaomi router, but the routes should be defined in either the firewall settings or the LAN settings.
This is an overview of what you are trying to accomplish: https://www.tp-link.com/us/support/faq/560/
Now, the other thing to try would be to have either router be connected to the other so that you wouldn’t need static routes.