Can`t connect meeting using jitsi-meet flutter + custom jitsi-meet sdk

Hello. First, I`m appology to my bad english. I wanna help us for my jitsi-meet project.

I`m making Flutter app with jitsi-meet flutter package
and custom jitsi-meet sdk

When I use pre-build SDK, My meeting can connect from my app and computer web. but I can`t modify custom UI on my app.
[배스캠프 : 네이버 블로그]

Then, when I edit flutter project for use my custom SDK like this.
[배스캠프 : 네이버 블로그]
It can change UI but can`t connect between PC and Mobile.

How can I solve it?

If is it bad way to edit UI, how can I edit custom UI in my app with flutter?