Hi! I understand you're experiencing crashes with the 3CX mobile app during video calls from outside to mobile clients. Let's get this sorted out for you.

To start, could you tell me which mobile OS you’re using (Android or iOS) and the version of the 3CX app installed? Also, does the crash happen right when the video call starts, or after some time into the call? Any additional context helps.

Meanwhile, here are some general troubleshooting steps for 3CX mobile video call crashes:

1. Update the App: Make sure you have the latest version of the 3CX app from the Google Play Store or Apple App Store. App updates often contain crash fixes.

2. Check Device OS Updates: Sometimes, older OS versions can conflict with the app. Verify your phone OS is updated to the latest stable version.

3. Restart the Device: Simple, but it can clear temporary glitches causing crashes.

4. Clear App Cache (Android only): Go to Settings > Apps > 3CX > Storage > Clear Cache. This can fix corrupted temporary files.

5. Review Video Codec Compatibility: The 3CX mobile app primarily supports certain video codecs (like H264). If the outside caller’s system uses a different codec, that could cause issues. You might want to test with a different SIP app on the outside caller side that supports H264, like Zoiper.

6. Check Network Conditions: Poor or unstable network connections can cause the app to behave unexpectedly during video calls.

If you’ve tried these already or crash persistently, there may be a deeper issue such as app conflicts, logs indicating the problem, or specific bugs with certain app or OS versions.

Let me know what you’ve tried or if you see any error messages before the crash. Also, I can help guide you to collect crash logs if needed, which can help escalate to 3CX support for a permanent fix.

Are you able to share more details? That way, I can offer the most accurate next steps.