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If you’re getting the “Protocol negotiation failed” error on TeamViewer, we’ve assembled some fixes below.
(You can always contact their support here).
According to the TeamViewer (TV) support community, this error occurs when connecting to a remote control, or another server or host using TeamViewer.
If there’s some sort of connection problem, you’ll get an error message that reads “Protocol negotiation failed. Please try again.”
According to TV, they say that the reason for this error is that on the TeamViewer host, it has received the incoming connection, but the actual remote control session was dropped and therefore not established.
What Causes It?
It apparently has a variety of causes- we can’t point to one thing specifically. More of a generic, catch-all error.
TeamViewer Support Fixes (#1)
To fix it, try some of the troubleshooting steps below from the TV support forums so that the remote control via TeamViewer can connect properly:
- Reboot TeamViewer by closing and re-opening the TeamViewer app
- Reboot the TeamViewer service in within Control Panel (Control panel > Administrative Tools > Services and then Under ‘Name’ find the Teamviewer11 process. Select it, then right-click it and select restart.)
- Experiment with disabling your firewall, including Windows or a third-party firewall service.
- You can also try to disable an IPS (Intrusion Prevention System).
- Temporarily deactivate your anti-virus protection- or try excluding the
- TeamViewer folder or its executable from anti-virus scanning.
- Try uninstalling and reinstalling TeamViewer.
Protocol Negotiation Failure (Video Fix)
TeamViewer Support Fixes (#2)
However, a couple days after a successful connection, he was unable to connect TV. The laptop, it showed an Incoming Connection but then a Protocol Negotiation Failure message.
On the smart device, it said that the connection was disconnected and was attempting to reconnect but wasn’t able to. He was using TV version 10.0.93450 on the laptop.
Strangely, he was able to connect to his Windows 8 desktop computer from the smart device. But he was experiencing the TeamViewer connectivity error when trying to connect to the laptop computer from a range of smart devices including a Kindle Fire & Apple iPad, so he theorized that the issue is obviously only with communication between his laptop and the tablet.
He had tried the following fixes to resolve this TeamViewer error, and while none worked for him, we figured it’d make sense to publish some of his attempts to see if they might work for you:
- Re-booted TV
- Disabled the laptop’s firewall
- Rebooted the smart tablet
- Temporarily disabled the antivirus
- Restarted the laptop computer
- Uninstalled and reinstalled TeamViewer on the tablet
- Installed the latest version of TeamViewer on the laptop computer
- Made sure that IPv6 was disabled
- Tweaked TeamViewer to permit all Windows logon for all users
- Set up TeamViewer for use with and without UDP (User Datagram Protocol)
- Un-installed every recent laptop update
- Re-booted the notebook in Safe mode with networking
Protocol Negotiation Failure (Video Fix #2)
Super User Fixes
A Super User poster fixed the problem by tweaking the firewall- he disabled NIPS protection (low and middle severity).
Another user commented that you’re able to access and then disable the Firewall entirely by going to Administration -> Services -> Windows Firewall.
Be careful though- Super Users say that it’s not recommended to mess with these settings unless you know what you’re doing.
Another Super User found a solution- it turns out the computer he was on was seriously contaminated with adware and a few viruses.
While he wasn’t sure which ones specifically were causing the connection issue, he speculated it was to block TV from a third-party providing remote technical support.
They used a different third-party remote software called Remote Utilities to fix it using MalwareBytes combined with Avira after which TeamViewer began operating again.
We hope one of these fixes resolved your connectivity error- as we said at the start, try opening a support ticket. This error can occur on Windows, Linux, as well as Mac operating systems.