Installed new router and airport utility can no longer see air express
I had been using Air Express to stream music to a sound system for several years. Recently I replaced the old router with an ASUS router. Everything in wifi network (iPhones, iPads, Apple TV) is working except for Air Express. I've reset the Express to factory settings. Express's amber light is blinking which I believe means the Express needs attention. But the Express never shows up on Air Utility. The router is set for both WPA and WPA2 authentication (Express can only do WPA) and I've disabled WiFi 6 mode.
What else should I check that could be preventing Air Utility from finding the Express?