TeamViewer lets you control a computer, phone or server remotely, for support calls, home-office access or managing machines in another building. A session normally starts by entering the partner’s TeamViewer ID, and the connection is brokered by TeamViewer’s servers before data flows between the two devices.
The check here asks teamviewer.com for a response from an outside server. It covers the company website. The connection brokers and the management console run separately, so the result is a starting point, with TeamViewer’s status page carrying the details per component.
Why a TeamViewer session fails
A remote session needs four things working at once: your app, the partner’s device, both internet connections and TeamViewer’s servers in between. When the session will not start, the fault is usually on one of the two ends.
Remote session troubleshooting
- Look at the status line in the app
If it does not show that the app is ready to connect, your device cannot reach TeamViewer’s servers.
- Wake the remote device
Sleep, hibernation and pending restarts are the most frequent reasons a partner shows as offline.
- Allow outgoing connections
Company firewalls must let TeamViewer reach its servers; the support site lists the ports it uses.
- Update both ends
Mismatched or very old versions refuse to connect or show odd errors.
- Check the account email
A new-device confirmation must be approved before your account works on that machine.
- Restart the TeamViewer service
On Windows, restarting the service from Services or rebooting the computer clears most stuck states.
Symptoms at a glance
| What you see | Likely cause | What to try |
|---|---|---|
| App says it is not ready | No route to TeamViewer servers | Check firewall, proxy and internet |
| Partner shown offline | Remote device asleep or service stopped | Wake the device, start TeamViewer |
| Session ends after a short time | Free license flagged for commercial use | Check license, contact TeamViewer |
| Black screen in session | Remote display asleep or locked | Send a key press, check display settings |
| Cannot sign in to the console | Account confirmation pending | Approve the email TeamViewer sent |
Different products, different failures
TeamViewer now ships several apps. The main remote access client runs on Windows, macOS, Linux, iOS and Android. A smaller QuickSupport app is used by people who only receive help. Companies manage devices through a web-based console, and unattended access depends on the TeamViewer service starting automatically on each machine. A console outage blocks management tasks but often leaves direct ID connections working, and vice versa. The status page lists components separately, which helps decide which one is affected.
Peak times and network quality
Remote sessions are most sensitive at the start of the working day, when support teams and home workers connect at once, and on networks with little upload bandwidth. A slow home connection on the remote side makes the screen update in jumps even though TeamViewer itself is healthy. Lowering the display quality in the session toolbar and closing video calls on the remote side makes a bigger difference than any setting on your own computer.
Ports, proxies and company networks
TeamViewer prefers an outgoing connection on port 5938. When that port is closed, it falls back to port 443 and then to port 80, the same ports normal web traffic uses. That is why it works on most home networks without any setup. On strict company networks it can still fail: a proxy that requires sign-in, a firewall that inspects encrypted traffic, or a rule that blocks remote access tools by name all stop the app from becoming ready. The proxy settings in TeamViewer’s advanced options can be pointed at the company proxy, but blocking rules are a decision for the network’s administrators, and the honest fix is to ask them.
Scam calls that use TeamViewer
Remote access tools are a favorite of tech support scammers. The pattern is familiar: a pop-up or a phone call claims the computer is infected, and the caller asks you to install TeamViewer and read out the ID and password. Once connected, they can see everything and take control. Microsoft, banks and internet providers do not cold-call people to fix their computers.
If you already gave someone access, close TeamViewer at once, disconnect the computer from the internet and change passwords from a different device, starting with email and banking. Then open the TeamViewer account, remove any devices you do not recognize and set a new password for unattended access, so the same people cannot simply connect again later. TeamViewer publishes advice on this kind of fraud on its support pages.
When the app refuses to connect and the check above is normal, confirming whether an outage reaches beyond your own network separates your setup from TeamViewer’s servers.
Official TeamViewer help
- TeamViewer Statusstatus.teamviewer.com
- TeamViewer Customer supportteamviewer.com/support
Questions about TeamViewer
Why does TeamViewer say it is not ready?
The app shows that it is not ready when it cannot reach TeamViewer's connection servers. A firewall, a proxy or a short network drop is the usual reason. Restart the app, check that outgoing connections are allowed and, if the check above fails as well, wait for TeamViewer to resolve the incident.
Why is the remote computer shown as offline?
The remote machine must be powered on, connected to the internet and running TeamViewer. A sleeping laptop, a Windows update restart or a TeamViewer service that did not start leaves the device offline. Ask someone at that location to wake the computer or start the app.
Why are my free sessions cut short?
TeamViewer offers the free version for personal use only. If its systems detect use that looks commercial, sessions can be limited or end after a short time. That is a license decision, not an outage. TeamViewer has a form on its site to request a review if you believe the detection is wrong.
Do both computers need the same TeamViewer version?
Very old versions can stop connecting to newer ones and to TeamViewer's servers. Keep both sides on a current release. Updating the remote side can be hard when nobody is there, so plan updates while someone is on site.
Can TeamViewer work when its servers are down?
Connections by TeamViewer ID go through TeamViewer's servers, so they fail during a server incident. Direct connections inside the same local network can be enabled in the settings and keep working on that network, which helps an office whose devices are all in one building.
Why did TeamViewer ask me to verify my account?
Signing in on an unfamiliar computer or from an unusual place triggers a confirmation email from TeamViewer. Until you approve it from that email, the account cannot be used on the new device. Look in spam and promotions folders if the message does not arrive.