Switched from Community 2024.2 to licensed 2025.1, portal doesn't work, error 404

I'm not so experienced in administering IRIS but as far as I understand IRIS for Health community comes with a web server out-of-the-box while licensed editions require Web Gateway to be deployed.

I was able to install dockerized instances of IRIS for Health 2025.1 along with Web Gateway, double checked that _SYSTEM and CSPSystem users are not locked, changed passwords for both, configured the gateway to connect to IRIS, then created a web gateway app (/iris) and checked the connection is OK. Now I'm struggling with accessing Management Portal. Neither of stereotype URLs - /iris, /csp/sys/UtilHome.csp, /iris/csp/sys/UtilHome.csp - work, all return 404. What am I doing wrong?