Problem uploading app to AppStore TestFlight with embedded

We are exploring the use of to embed in a retail app we have under development. We have just uploaded the first, beta version to the Apple AppStore to test using TestFlight and it has failed due to use of a PrivateAPI. This API is part of the JitsiMeetConferenceOptionsBuilder class and is used as here
fromBuilder:^(JitsiMeetConferenceOptionsBuilder *builder) {
builder.serverURL = [NSURL URLWithString:@“”];

The error message returned by the AppStore upload is "The app references non-public selectors in setServerURL.