Troubleshoot Calls Dropping

Troubleshooting3 min readUpdated 2026-03-12

Troubleshoot Calls Dropping

If your calls disconnect mid-conversation without either party hanging up, use this guide to find and resolve the issue.

Available on: All plans

Common causes

Cause	How to identify	Fix
Unstable network	Calls drop when Wi-Fi signal fluctuates or bandwidth spikes	Switch to wired Ethernet; close bandwidth-heavy apps
VPN interference	Calls drop only when VPN is active	Disable VPN or configure split tunneling to exclude JustCall traffic
Firewall blocking UDP	Calls connect but drop after a few seconds	Ask IT to open UDP ports 10000-60000 for voice media
Browser memory pressure	Calls drop after long sessions or with many tabs open	Close unused tabs; restart browser every few hours
Call time limits	Calls end at exactly the same duration each time	Check your plan's per-call time limit in account settings
Browser or app crash	Call ends abruptly with an error message or blank screen	Update browser to latest version; clear cache

Step-by-step troubleshooting

1. Test your network stability

Run the JustCall network test at Settings > Network Test. Look for:

Packet loss above 1% — causes audio gaps and disconnections
Jitter above 30ms — causes instability in the voice stream
Latency spikes — intermittent high latency causes timeouts

If your network test shows poor results, try a wired connection before investigating further.

2. Disable your VPN

VPNs route voice traffic through distant servers, adding latency and packet loss. Temporarily disable your VPN and test a call. If calls stop dropping, configure your VPN to exclude:

*.justcall.io
*.twilio.com
UDP ports 10000-60000

3. Check firewall rules

JustCall voice calls require UDP ports 10000-60000 for media traffic. If your firewall blocks outbound UDP, calls may connect (via TCP signaling on port 443) but drop once the media stream fails. Ask your IT team to verify these ports are open.

4. Reduce browser load

Each open browser tab consumes memory. If Chrome is using more than 2 GB of RAM, close unnecessary tabs and extensions. You can check memory usage at chrome://task-manager.

5. Check call time limits

Some JustCall plans have per-call duration limits. Go to Settings > Account and review your plan details. If calls consistently drop at the same time mark (e.g., 60 minutes), this is likely a plan limit.