Hi VAPI team We're experiencing crashes in production when users start voice calls on unstable mobile signal. The app works fine on WiFi but freezes and gets killed by iOS on poor connectivity. We've traced the root cause via Sentry to daily_flutter, which your Flutter SDK depends on. Specifically, CallClient.create() in daily_flutter runs a native FFI call synchronously on the main thread. On poor signal, this blocks for >2 seconds and iOS terminates the app. Our developer has raised this as an issue on the daily-co/daily-flutter GitHub repo but hasn't had a response yet. Given your relationship with Daily.co, could you help escalate this on your end? Is this something you're aware of, and are there any workarounds or alternative approaches you'd recommend in the meantime? Happy to share Sentry crash data if helpful. Thanks

Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team

Hey, thanks for flagging this and for digging into the root cause. A blocking FFI call on the main thread under poor connectivity would definitely explain the iOS crash. I can help escalate this with the Daily team, but in the meantime it’d help to see the Sentry crash trace and where CallClient.create() is triggered in your call flow. Are you initializing it during UI startup or right when the call begins? @ChrissyD

Hey @James Christopher - here's the Sentry issue (public link): https://ptpal-ltd.sentry.io/share/issue/84e45259776c467eace19011278a6880/ To answer your questions: - CallClient.create() is called when the user starts a call, not at app startup - Our VAPI SDK fork already has a 10-second timeout + 5 retries on CallClient.create(), but the native blocking bypasses those - Reliably reproducible on poor mobile signal, fine on WiFi - 26 events, 2 users affected, ongoing Heads up — dSYMs haven't been uploaded for this build yet so the stack trace is partially redacted, but you can clearly see 5 consecutive daily_flutter frames as the source. Working on getting the symbols uploaded. We've also opened a ticket on the daily_flutter repo. Let me know what else would help.

hey there, we reported the issue to [daily.co](http://daily.co). we will provide an update once we hear back from them.

Awesome thank you!

please check your DMs. we sent you a couple questions