The short version
- 01Record the complete code and when the connection fails.
- 02Compare with another permitted network on the same device, if available.
- 03Ask the network administrator to review Zoom's firewall and proxy requirements.
- 04Review possible antivirus interference with the administrator or software provider.
- 05Use the standard uninstaller, then reinstall from Zoom's official Download Center.
- 06Ask your internet provider whether Zoom is reachable if the connection still fails.
Raw message
Error code: 5003
Likely causes
- The device cannot connect to Zoom's servers.
- A firewall, proxy or security product may interfere with that connection.
Establish which connection fails
Zoom's 5003 article identifies a connection failure to its servers and names firewall, proxy and antivirus interference as checks. Our recommendation is to compare the same device on another permitted network. Record the result; it helps the administrator choose where to investigate without proving a particular cause.
Give the administrator the current network requirements
Zoom's network document separates Meetings/Webinars from other products and lists outbound traffic and return connections. Ask the administrator to use the applicable table, including its current domains, ports and IP ranges. These are not instructions to add inbound router port forwarding.
The document also covers HTTPS/SSL proxy connections. Review that guidance if a managed proxy or inspection system is involved, rather than copying an old IP list. Zoom's 5003 article directs remaining reachability questions to your internet provider.
Use the standard uninstall route
On Windows, use Control Panel's Uninstall a program and select Zoom Workplace or zoom.us. On Mac, use the Zoom Workplace menu's uninstall option. Reinstall from the official Download Center; ask IT to handle an organization-managed installation.
Zoom also documents deeper cleanup tools, but warns that CleanZoom and keychain cleanup can remove encryption keys for Zoom Mail and encrypted Zoom Phone voicemail. Use the ordinary uninstall path for this check; deeper cleanup needs the backup or escrow arrangements described by Zoom.
Sources and review notes
Checked on . Official Zoom documentation checked October 1, 2026. Comparing permitted networks and recording results are editorial guidance. Network rules vary by Zoom product. This reference covers 5003 only. Glitchary is independent of Zoom.