OK, while you try to connect your AM5 with the Indi driver via serial, do you also have the AM5 connected to the ZWO AM5 app via WiFi? That may be the reason why Indi won't connect via serial; dual connection, WiFi with the ZWO app and serial connection via Indi is likely not allowed so you should disconnect the mount from the ZWO AM5 app. Attached is a screenshot of my Indi screen for the ZWO AM5. I do not use the ZWO app nor do I try to connect via WiFi.

Hope this helps.