How to deal with transitionTo in FastBoot and Nginx?

I run up FastBoot on port 3443 and use nginx as the reverse proxy. There are the next lines in nginx config file:

proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $host;
proxy_set_header X-NginX-Proxy true;

When in some place called transitionTo FastBoot tries to redirect to host myhost.com:3443 but port 3443 isn't public. How can I make FastBoot doesn't add the port to my host?