When Zoom error code 104103 appears, it usually means Zoom connectivity is being blocked somewhere between your device and the service. This guide explains what error 104103 indicates, why network policies often trigger it, and how to restore meeting access with clear, practical steps.
Small Detail That Matters: Treat Zoom error code 104103 as a connection path issue first. If the same device works on a different network, the cause is almost always firewall, proxy, or a security gateway.
- Write down the exact message that accompanies 104103 and whether it happens at sign-in or when you join a meeting.
- Test once on a second connection (mobile hotspot is enough) to confirm whether Zoom connectivity changes.
- If you are on a managed network, expect network allow-listing to be involved for error code 104103.
Table of Contents
Meaning Of Zoom Error Code 104103
Zoom error code 104103 indicates that a problem is preventing your device from establishing a working connection to Zoom servers. In plain terms, the connection is blocked or cannot be completed, so the app cannot continue the sign-in or meeting join process. ✅Source
What This Usually Means: the signaling connection that starts Zoom connectivity is failing. Fixes often focus on DNS, proxy settings, or a firewall rule.
Common Situations Where 104103 Shows Up
Joining A Meeting
Zoom error code 104103 may appear right after you paste the meeting link or enter an ID. The app starts connecting, then fails before audio/video can initialize.
- Most common on networks that require allow-listing for new services.
- Also common when a VPN changes routing mid-connection.
Signing In Or Starting The App
error 104103 can appear as the desktop app launches or during sign-in. In this case, proxy authentication and security gateway rules become more likely.
- Typical on corporate Wi-Fi with web filtering or strict outbound rules.
- Also happens if Zoom connectivity is blocked only for certain protocols.
Why Error Code 104103 Happens
Zoom error code 104103 is not a single-root-cause error. It is a connectivity symptom. The pattern is consistent: something interrupts the path between your device and Zoom endpoints, so the connection cannot be established or maintained.
- Firewall rules block required outbound ports, or allow HTTPS only in a way that breaks real-time media.
- Proxy settings force traffic through a gateway that Zoom cannot use reliably for audio/video transport.
- Security inspection (deep packet inspection or SSL/TLS inspection) introduces delays or blocks sessions that look like Zoom connectivity failures.
- DNS issues resolve the wrong address, fail to resolve, or use a filtered resolver that blocks Zoom domains.
- Outdated app or OS support gaps limit compatibility, and error 104103 becomes visible during initial connection attempts.
Fast Checks Before Deep Troubleshooting
Time Saver: Do these quick validations once. They often isolate Zoom error code 104103 to either a service status issue or a local network policy issue within minutes.
- Check the official Zoom Service Status page. If there is an active incident, Zoom connectivity may fail even on healthy networks. ✅Source
- Try the same meeting link from a different network (mobile hotspot is fine). If error 104103 disappears, the original network is filtering or blocking traffic.
- Open a normal website in a browser from the same device. If it triggers a sign-in page, complete the captive portal flow before retrying Zoom error code 104103.
- Disable any VPN or manual proxy temporarily, then retry once.
Step-By-Step Fixes For Most Users
Start with the simplest actions that restore Zoom connectivity. Each step targets a common cause of Zoom error code 104103 without changing advanced network policy settings.
Turn Off VPN And Remove Manual Proxy Settings
- Close the Zoom Workplace app, turn off any VPN, then reopen Zoom and retry.
- If you set a manual proxy at the OS level, switch it back to automatic detection, then test error 104103 again.
- On managed devices, a policy-enforced proxy can still apply. In that case, jump to Firewall and Proxy guidance.
Restart The Connection Path
- Restart your router (or toggle airplane mode on mobile). This forces a clean route and can clear Zoom connectivity failures.
- Switch Wi-Fi bands (2.4 GHz to 5 GHz, or the reverse). A noisy channel can worsen Zoom error code 104103 symptoms.
- Try wired Ethernet if available. Fewer variables, faster isolation of wireless interference.
Update Zoom Workplace To The Latest Version
New releases often include fixes for connection stability and sign-in flows. In the desktop app, open your profile menu and use Check for Updates. If your app is managed and the update option is missing, your IT team may control updates, which can affect Zoom connectivity and show error 104103 until a newer build is deployed. ✅Source
Reinstall The App When The Error Is Persistent
If Zoom error code 104103 persists across restarts and networks, a clean reinstall can remove corrupted local configuration that breaks Zoom connectivity. Uninstall the app, restart the device, then install again from the official download location. Keep this step after the network checks, since firewall issues will remain even after a reinstall.
Firewall And Proxy Requirements For IT Teams
On managed networks, Zoom error code 104103 often clears only after outbound rules allow the required protocols. Zoom publishes a detailed list of ports, domains, and service rules for Zoom connectivity; if your environment uses allow-lists, align with that documentation first. ✅Source
| Traffic Type | What To Allow | Why It Matters For 104103 | Practical Notes |
|---|---|---|---|
| Core Signaling | TCP 443 (and in some cases TCP 80) to Zoom domains | If signaling cannot complete, Zoom connectivity fails early and surfaces error 104103. | Prefer direct outbound access without forced authentication loops on proxies. |
| Meetings And Webinars | TCP 443, 8801, 8802 | Helps clients establish stable sessions when 443 alone is constrained by network policy. | Keep outbound return connections permitted as well. |
| Real-Time Media | UDP 443 and UDP 3478, 3479, 8801–8810 | Media paths are sensitive. When blocked, the app may stall or fail and show Zoom error code 104103. | If UDP must be restricted, plan for reduced resilience and test meeting join flows carefully. |
| Allow-Listing Model | Zoom domains and published service ranges | Strict allow-lists can inadvertently block newly used endpoints, which looks like Zoom connectivity loss. | Use the vendor-maintained lists rather than static guesses to reduce recurring 104103. |
Helpful Diagnostic Pattern: If the same device on the same app version works on a hotspot but fails on the office network, Zoom error code 104103 is very likely tied to proxy, firewall, or security gateway rules.
Security Inspection and Packet Filtering Considerations
Some security stacks perform packet inspection and SSL/TLS inspection on outbound traffic. That can be valuable for governance, yet it can also add delay or break sessions that depend on stable, low-latency transport. Zoom’s network guidance highlights that deep inspection on real-time Zoom traffic can introduce meaningful delay, and it recommends policies that avoid SSL/TLS inspection for Zoom traffic while still maintaining security via SRTP. ✅Source
- If your gateway inspects traffic, test a rule that exempts Zoom connectivity from deep inspection and re-test Zoom error code 104103.
- If your firewall supports application-aware policies, apply a specific allow policy for Zoom applications to reduce false positives.
- Avoid routing internal-to-internal Zoom traffic through an external proxy when possible. Extra hops can look like instability and amplify 104103 occurrences.
Device And App Health Checks
Zoom error code 104103 can also surface when a device is running an OS that is no longer supported by the current desktop app, or when required components cannot update reliably. Zoom publishes supported operating systems and notes that support for older Windows versions ended with a defined release, which can leave devices stuck on older builds and more exposed to Zoom connectivity failures. ✅Source
- Confirm you are on a supported OS and using a current Zoom Workplace app build.
- Restart the device once after updating. A clean restart can reset network drivers and services.
- If the device is managed, confirm required update components are allowed by policy so Zoom connectivity is not blocked by missing dependencies.
Windows Network Resets When Nothing Else Works
If Zoom error code 104103 persists on a Windows device across multiple networks, a reset of local network state can help. Microsoft documents a practical sequence of commands that reset Winsock, reset the TCP/IP stack, release and renew the IP address, and clear the DNS cache, plus a built-in Network reset option as a last step. Use these only if you understand the impact on VPN clients and saved network settings. ✅Source
Command Prompt Notes: Run as administrator. Reboot after the sequence. Then test Zoom connectivity once before changing more settings. If error 104103 continues only on one network, return focus to firewall and proxy rules.
- netsh winsock reset
- netsh int ip reset
- ipconfig /release
- ipconfig /renew
- ipconfig /flushdns
What To Share With IT When You Escalate
When a managed network is involved, the fastest resolution of Zoom error code 104103 comes from giving IT precise context. Keep it short. Focus on connection path facts, not guesses. Include timestamps, network type, and whether the same device works on another network.
| Detail | Why It Helps |
|---|---|
| Exact error text and 104103 | Confirms this is a Zoom connectivity block rather than a meeting-specific error. |
| Where it happens (sign-in, join, after “connecting”) | Guides whether to focus on proxy auth, DNS, or media ports. |
| Network type (office Wi-Fi, guest Wi-Fi, wired) | Guest networks often have different firewall rules that affect 104103. |
| Hotspot comparison (works or fails) | Strong indicator of whether the root cause is the network policy. |
| VPN/proxy status (on or off) | Eliminates common routing causes of Zoom error code 104103. |
FAQ
Is Zoom Error Code 104103 an account problem?
Zoom error code 104103 is typically a Zoom connectivity problem, not an account issue. If your account works on another network or device, that is strong evidence the connection path is being blocked rather than your credentials.
Why does 104103 happen only on office or school Wi-Fi?
Managed networks often enforce firewall rules, proxy routing, and security gateway controls. If those controls do not allow the required ports and domains, Zoom error code 104103 appears because Zoom connectivity cannot complete.
Does disabling a VPN really help with error 104103?
Yes, it can. A VPN changes routing and can force Zoom traffic through a path where proxy or firewall policies apply differently. If turning off the VPN stops Zoom error code 104103, the issue is tied to the route, not the meeting.
What is the difference between “connecting” and 104103?
“Connecting” is a general state. Zoom error code 104103 is a specific failure result that indicates the app cannot establish a working session to Zoom’s services. In practice, persistent “connecting” followed by 104103 points to a blocked connection path.
Can an outdated Zoom version cause 104103?
It can contribute. Older builds may be limited by OS support or policy-controlled updates, and that can surface as Zoom connectivity failures in some environments. Updating the Zoom Workplace app is a low-risk first action when troubleshooting Zoom error code 104103.
When should I ask IT to change firewall settings?
If Zoom error code 104103 happens only on a managed network and works on a hotspot, involve IT early. Provide the time of failure and confirm whether Zoom connectivity fails at sign-in or meeting join. That directs them to firewall and proxy rules instead of device-level changes.