Work this in order. The sequence matters: each step rules out a whole class of cause, so skipping ahead usually means backtracking.
1. Establish what “not working” means
- Does the client open at all?
- Does it accept the sign-in, then drop?
- Does it connect but the destination still fails?
- What is the exact error text?
2. The checks that resolve most tickets
- 1
Confirm general internet access first
If a normal website will not load, the VPN was never the problem. Fix connectivity first.
- 2
Check for a captive portal
Hotel, airport, and café networks intercept traffic until a sign-in page is accepted. VPN clients fail confusingly behind these. Have them open any website and complete the portal.
- 3
Verify credentials against a known-good service
Have them sign in to email in a browser. This separates an account problem from a VPN problem in about fifteen seconds.
- 4
Confirm multi-factor completion
Many VPN failures are an unapproved or timed-out second factor. Ask specifically whether a prompt appeared and whether they approved it.
- 5
Fully quit and reopen the client
Closing the window often leaves it running. On macOS quit it properly; on Windows close it from the system tray.
- 6
Restart the device
Genuinely effective for stuck network adapters after sleep. Worth doing before anything invasive.
- 7
Test a different network
A phone hotspot is the fastest way to prove whether the problem follows the device or stays with the network.
3. Signals to escalate
- Multiple unrelated users report VPN failures in the same window — check service status before troubleshooting individuals.
- The client connects on one network but never on the user's home network, after a hotspot test.
- An error referencing certificates, licences, or capacity.
- The user's role requires VPN eligibility they may not have been granted.