If you see Zoom Error Code 104118, the app is usually telling you one simple thing: your device cannot complete a reliable connection to Zoom services. The fastest fixes come from treating this as a network path problem first, then narrowing it down to a firewall, proxy, VPN, DNS, or local network stack issue. Zoom groups 104101–104118 as connectivity errors, so the troubleshooting approach is consistent across this range.[✅Source-1]
This guide stays focused on fixing 104118 on Windows, macOS, and common managed networks, with clear checks you can run in minutes.
First Stop: Verify Service Availability
- If the error started suddenly for many people at once, check Zoom service status before changing anything on your device.
- If a maintenance window or incident is listed, your best move is to retry later and avoid unnecessary network changes.
Zoom publishes current incident and maintenance updates through its official status resources.[✅Source-2]
Table of Contents
What Error Code 104118 Usually Signals
Zoom Error Code 104118 appears when the client cannot establish or maintain the connection it needs to join a meeting or reach key Zoom services. Most of the time, the trigger is one of these: a blocked route (firewall/proxy), a forced route (VPN), unstable Wi-Fi, or a name resolution problem (DNS).
- Typical moment You click Join, then it fails before you enter the meeting fully.
- Common clue A browser can open normal sites, but Zoom traffic fails.
- Strong hint Mobile hotspot works, office Wi-Fi does not.
| What You Observe | Likely Reason | Best Next Move |
|---|---|---|
| 104118 only on office network | Proxy, SSL inspection, or firewall policy | Jump to Firewall Or Proxy checks and share port/domain needs with IT |
| 104118 on Wi-Fi but not on Ethernet | Weak signal, interference, router firmware issues | Try wired, move closer, reduce congestion, then retest |
| Works for others, fails only on your device | Local network stack, cached DNS, security software rules | Run Zoom diagnostics, then do DNS and network stack repair |
| Fails in browser join and app join | Network path to Zoom services is blocked | Test from another network, then focus on firewall/VPN path |
Fast Checks That Often Resolve It
These steps are low-risk and frequently clear Zoom Error Code 104118 without touching firewall policies. Keep your focus on connectivity and repeat the same join attempt after each change.
Home Network Checks
- Close Zoom completely, reopen it, then try Join again.
- Restart your router/modem (power off, wait, power on).
- Switch to Ethernet if available, even temporarily.
- Try a different Wi-Fi band (2.4 GHz vs 5 GHz), then retest.
Work Network Checks
- If you are on a VPN, disconnect and retry (if policy allows).
- Try a mobile hotspot once to confirm this is a network-policy issue.
- Join a known test meeting to remove meeting-specific variables.
- Note the exact time of failure for IT logs.
Use A Test Meeting To Confirm The Problem
Open the official Join a Test Meeting page and try to join from the same device and network. If the test also fails with 104118, you have confirmation that the issue is the connection path, not a specific meeting link.[✅Source-3]
If joining is only failing from the Zoom client but web join works for you, it can still point to a local rule blocking the app. Zoom’s official join-troubleshooting flow also recommends reinstalling when the app itself becomes the bottleneck.[✅Source-4]
Firewall And Proxy Blocks
When a firewall or proxy blocks the ports or domains Zoom needs, Zoom Error Code 104118 can appear even if “normal internet” looks fine. The most important detail: Zoom uses HTTPS for signaling and UDP for real-time media, so a network that only allows basic web browsing can still block meetings.
| Purpose | Protocol | Ports (Outbound) | Why It Matters For 104118 |
|---|---|---|---|
| Core Zoom connectivity | TCP | 80, 443 | Sign-in, web resources, and primary service access |
| Core Zoom connectivity | UDP | 443 | Helps maintain stable transport on some networks |
| Meetings and webinars | TCP | 443 (and some environments may use 8801, 8802) | Client-to-service control and session setup |
| Meetings and webinars media | UDP | 3478, 3479, 8801–8810 | Audio/video streams; blocks here often surface as connectivity failures |
| Required destinations | Domains | *.zoom.us and *.zoom.com | Allowlisting domains is often simpler than IP-only policies |
These port ranges and domains are documented in Zoom’s official firewall and proxy guidance. If you are on a managed network, share the table above with your network team and ask them to confirm outbound access for Zoom meetings traffic.[✅Source-5]
If A Local Firewall Is The Only Block
On Windows, a practical approach is to allow the Zoom app through the firewall for the network profile you are currently using (Private or Public), rather than turning the firewall off. This keeps protection in place while restoring Zoom connectivity.[✅Source-6]
VPN Split Tunneling For Zoom
A VPN can turn a clean route into a congested one, or send Zoom media through security controls that are not designed for high-volume real-time traffic. If your organization supports it, the most effective fix is usually split tunneling for Zoom’s real-time ports, while keeping corporate traffic protected.
Zoom explicitly recommends split tunneling to allow UDP 8801–8810 and TCP 443 to Zoom destinations (commonly *.zoom.us and *.zoom.com) so meetings can route efficiently while corporate data remains on the VPN.[✅Source-7]
Zoom Network Connectivity Tool
If you want a clean, evidence-based path to the fix, run the Zoom Network Connectivity Tool. It can reveal proxy detection, show service reachability, and help you separate “local device” issues from “network path” issues. The tool also supports tests that Zoom Support may ask for when diagnosing 104118 connectivity failures.[✅Source-8]
How To Open It
- Windows: Ctrl + Alt + Shift + D
- macOS: Cmd + Option + Shift + D
What To Look For
- Service status for Meetings and Team Chat
- Proxy detection you did not expect
- High packet loss or unstable latency on the meeting test
If the tool shows connectivity failures only to Zoom services while other traffic is fine, that’s strong support for a firewall/proxy/VPN rule being the root cause. Save the results for your IT team or support case.
Wi-Fi And Router Stability Checks
Unstable Wi-Fi can surface as a connection failure during session setup, especially when the app switches between UDP media paths and fallback transports. If you can, validate with a wired connection for one test; it is a simple way to separate “signal quality” from “policy blocking.”
- Move closer to the router or access point and retest.
- Switch to Ethernet once, even temporarily.
- Upgrade router firmware if updates are available.
- Reduce local congestion by pausing large uploads during the join attempt.
Zoom’s Wi-Fi guidance prioritizes trying a wired connection, improving signal quality, and addressing bandwidth constraints when meetings disconnect or behave inconsistently.[✅Source-9]
DNS And Network Stack Repair
If Zoom Error Code 104118 is happening only on one device, after you have verified firewall rules and VPN behavior, the remaining suspects are often DNS cache, corrupted network settings, or a local security rule. The fixes below are standard, quick to reverse, and easy to test.
Flush DNS Cache On Windows
This clears cached name lookups and forces fresh resolution, which helps when a stale DNS entry is sending Zoom traffic to the wrong place. The ipconfig command is Microsoft’s documented way to refresh DNS settings.[✅Source-10]
ipconfig /flushdnsReset Winsock On Windows
If networking APIs are in a broken state, resetting Winsock can remove problematic custom layers and return the catalog to a clean baseline. Microsoft documents winsock reset as a way to resolve network problems linked to corrupted Winsock settings.[✅Source-11]
netsh winsock resetRestart your PC after a Winsock reset, then try joining again. If the error disappears, the cause was likely a local networking layer rather than Zoom itself.
Adjust DNS Settings On Mac
On macOS, changing DNS servers for the active network service can quickly confirm whether the issue is tied to a resolver problem. Apple documents where to enter DNS servers in system network settings, which is often enough to clear Zoom connectivity edge cases.[✅Source-12]
- Open System Settings, then Network.
- Select your active connection, open Details, then DNS.
- Temporarily add a known DNS provider approved by your environment, apply, and retry Zoom.
Clean Reinstall When Settings Are Stuck
If you have confirmed the network path is valid (ports/domains reachable) and other devices can join, a clean reinstall can remove corrupted local settings that keep triggering 104118. Zoom provides official uninstall and reinstall steps, including a complete removal option for cases where configuration files are the problem.[✅Source-13]
Download The Latest Installer From The Official Source
After uninstalling, install the newest version from Zoom’s official Download Center to ensure you have current network components and compatibility fixes. This is also the safest way to avoid mismatched builds across devices.[✅Source-14]
When You Need IT Help
If you are on a managed network and Zoom Error Code 104118 only happens there, the fix is often a policy change. Keep your request specific: ports, protocols, and destinations. That keeps the conversation about connectivity requirements, not guesswork.
What To Send To IT
- Your location (home, office) and network type (Wi-Fi, Ethernet).
- Whether VPN is active, and the VPN client name.
- Exact timestamp of the failure.
- Whether the Zoom test meeting also fails.
- Whether hotspot works (yes/no).
What To Ask IT To Check
- Outbound access for TCP 443 and UDP 8801–8810 to Zoom destinations.
- Whether a proxy or SSL inspection is interfering with Zoom traffic.
- Whether the VPN tunnel forces Zoom media through the corporate path.
- Whether DNS filtering or web gateways are blocking Zoom domains.
Copy-Paste Message For A Support Ticket
Subject: Zoom Error Code 104118 – Network Connectivity Verification
Hello,
I am receiving Zoom Error Code 104118 when attempting to join meetings.
Environment:
- Device/OS:
- Connection: Wi-Fi or Ethernet:
- VPN: On/Off (client name if On):
- Timestamp of failure:
- Result on mobile hotspot (works / fails):
- Result on https://zoom.us/test (works / fails):
Request:
Please verify outbound connectivity to Zoom services, specifically allowing TCP 443 and Zoom meeting media over UDP 8801–8810 (and any required supporting ports), and confirm that proxy/SSL inspection is not disrupting Zoom traffic to *.zoom.us and *.zoom.com.
Thank you.FAQ
Is Zoom Error Code 104118 a login problem?
104118 is most commonly tied to connectivity between your device and Zoom services. If you can browse normally but Zoom fails, focus on firewall/proxy/VPN and the required ports.
Why does it work on hotspot but fail on Wi-Fi?
A hotspot test is a strong indicator that your primary Wi-Fi network is applying a rule or experiencing instability. The hotspot uses a different network path, so it bypasses local proxy policies or problematic routing. That points you toward firewall/proxy checks and router stability steps.
Do I need to open specific ports to fix 104118?
On managed networks, yes—many fixes come down to allowing TCP 443 and enabling real-time media over UDP 8801–8810. When those are blocked, Zoom connectivity can fail even if regular web browsing works.
What is the fastest diagnostic inside Zoom?
The Zoom Network Connectivity Tool is a fast, structured way to check service reachability and proxy detection. It provides practical signals like service status and connection tracing, which helps pinpoint where 104118 is coming from.
Will reinstalling Zoom remove the error?
If the network path is confirmed good, reinstalling can help by clearing corrupted local settings and stale configuration. A clean reinstall is most effective when only one device is affected and others can join normally.