Posted by houh04
Digon

Re: Cannot connect to Teamviewer server since yesterday

Ohh, I think I have some clue !! 

In my failed log with CSTNET, CreateMasterConnect() is trying to open port 5938, the very one which has not passed the telnet test!

2017/04/23 19:16:40.924  4080  5016 S0   Activating Router carrier
2017/04/23 19:16:40.924  4080  5016 S0   CProcessCommandHandlerMasterConnect[918]::CreateMasterConnect(): master15.teamviewer.com:5938, Connection 918, proxy=''
2017/04/23 19:16:45.925  4080  5036 S0   CTcpConnectionBase[918]::HandleConnectTimeout(). Connect timed out to master15.teamviewer.com:5938
2017/04/23 19:16:45.925  4080  5028 S0!  CProcessCommandHandlerMasterConnect[918]::HandleMasterConnect(): MasterConnect to 0.0.0.0 failed
2017/04/23 19:16:45.925  4080  5028 S0!!!Connect to Master master15.teamviewer.com / 185.188.32.5 failed!

while in my successful log with China Unicom 4G hotspot, CreateMasterConnect() is trying to connect port 443, which has succeeded in the telnet test:

2017/04/23 19:19:49.956  4080  5028 S0   Activating Router carrier
2017/04/23 19:19:49.956  4080  5028 S0   CProcessCommandHandlerMasterConnect[967]::CreateMasterConnect(): master6.teamviewer.com:443, Connection 967, proxy=''
2017/04/23 19:19:50.379  4080  5032 S0   CProcessCommandHandlerMasterConnect[967]::HandleMasterConnect(): Sending MasterCommand addonchannels=0&client=TV&f=Login&gw=1&gwlevel=431&hideonlinestatus=0&httpout=1&ic=-185770073&id=619826053&iguid={f3c60b81-1886-428b-8716-14c642165b08}&language=zhC ...

This explains why I got the same telnet result but different outcomes for Teamviewer connectivity.

So the question would be:

Is there any way to force Teamviewer to use port 443 (or maybe 80) instead of 5938? 

or 

How can I make port 5938 work?

Thanks!

Posted by hklebe
Digon

Re: Cannot connect to Teamviewer server since yesterday

I have tested it and only one of the 3 ports 80, 443 and 5938 is necessary for the usage of TeamViewer. The port 5938 is the default port, if this port not working or blocked, the client will try port 80 or 443. I guess, that your the firewall blocks the port 5938.

Also good tools for testing, but with more effort compared with standard tools:

tcping - this allows a TCP ping with a specific port, instead of standard ICMP ping

https://www.elifulkerson.com/projects/tcping.php

tracetcp (winpcap is required) - this allows a tcp traceroute with a specific port, instead of standard ICMP traceroute

https://github.com/SimulatedSimian/tracetcp/releases

At both tools, there are some parameters available... (e.g. IPv4 / IPv6, Port)

Posted by DomLan
Heptagon

Re: Cannot connect to Teamviewer server since yesterday

Hi,

try Option -> Advanced -> Advancenced Network Opts -> Use UDP (reccomended)... remove.

Regards

Domenico Langone
MCSD: App Builder
Posted by ily1605
Digon

Re: Cannot connect to Teamviewer server since yesterday

Finally, the connection is back in Shanghai with ISP of China Telecom just now

Posted by blkatbyhh
Digon

Re: Cannot connect to Teamviewer server since yesterday


@houh04 IPv6 is too complex for me, I am not sure which one of these teredo or 6to4 or ISATAP fits my condition。 I am using a PC with windows 10, I just enabled IPv6 in the properties window of the LAN device

Anyway, CERNET seems back to normal, one of my IPv4-only PC have teamviewer online. Thanks for the technician team and good luck for the others.

@houh04 wrote:

@blkatbyhh wrote:
Guys if your ISP support ipv6 and you can enable ipv6, it will help your teamviewer back online. At least it works for me in CERNET. But not every ISPs and devices support ipv6 so let's wait for the technician team to fix the problem and provide our help.

I'm thinking of two things:

1. How can I get a stable IPv6 connection in CSTNET ? Are you using tunneling for your IPv6 (Teredo, 6to4, ISATAP)?  @blkatbyhh

2. Why is IPv6 necessary for CSTNET anyway? It seems not to be needed for other ISPs, because when I connect my computer via my cell phone's hotspot, which is on China Unicom, Teamviewer gets its connection even with IPv6 disabled. I don't understand what's going on here (maybe some ports of IPv4 are blocked by CSTNET?) , but is there anyway to bypass IPv6 in my case?@Esther

Thank you guys in advance!

 


Posted by houh04
Digon

Re: Cannot connect to Teamviewer server since yesterday

Yes, my Teamviewer in CSTNET (even with IPv4) is back online right now after losing the connection for 1 week!! Many thanks to the support team and you guys.

Posted by tdf321
Digon

Re: Cannot connect to Teamviewer server since yesterday

China telecom connection is back to normal. Thanks

Posted by sim
Digon

Re: Cannot connect to Teamviewer server since yesterday


@sim wrote:

@Esther wrote:

Hi there,

it looks like most of our users can connect to the TeamViewer servers again.

However, some users are still having issues and I wanted to let you know, that we are working on it to get everybody back on track.

If you are still having issues to reach our servers, please try the following steps:

  1. Restart your TeamViewer service
  2. Make a DNS flush
  3. Check whether port 80, 443 or 5938 are open for outgoing connections
  4. Test whether a Telnet connection to one of our server is possible
    1. Do you get a completely blank screen with a blinking cursor? That means, everything is alright
  5. Check whether your FQDN entries on your firewall are up to date
  6. Whitelist *.teamviewer.com in your firewall

I am sorry for the inconveniences.

Best, Esther

Just leave a mark here, in case I got put into most users.:smileytongue:

And I'll leave another mark when I get back to normal.:smileyhappy:

Good luck to everyone else.


According to my acknowledgement, it's confirmed that the usage of most customers of Shanghai Telecom(both enterprise & personal business) has recovered back to normal this afternoon(about 2 pm o'clock on Apr 25th,2017, UTC+8)

And the same recovery also applied to those customers of China CERNET almost at the same time as well.

Thank you all for your hard working.:smileyvery-happy:

Best regards, Sim

Posted by rovguy
Henagon

Re: Cannot connect to Teamviewer server since yesterday

my shanghai office teamviewer back to normal after restarting china telecom modem, initially cannot work. I unplug my lan cable from china telecom modem to sonicwall. I plug back again, my teamviewer is back to normal again.

Posted by hklebe
Digon

Re: Cannot connect to Teamviewer server since yesterday

I have received also the same feedback from a customer in Shanghai.

He had a special device from china telecom and after a reboot of the device, everything worked again!!!

Posted by Champ14
Photon

Re: Cannot connect to Teamviewer server since yesterday

Hi,

 

Any Update on this? So this can be solve only by their ISP's? Are the ISP's aware and willing to check and fix this? Thanks!

Posted by Community Manager
Community Manager

Re: Cannot connect to Teamviewer server since yesterday

Hi there,

Here is a quick update from my side to keep you posted:

We continue to be in touch with the ISPs in question. We understand most users in Shanghai are able to connect to TeamViewer again.

If you are still experiencing connection issues and are working with a device that is using NAT, please try to un-plug and re-plug this device. This may resolve the issue.

All the best,

Esther

Posted by wahayd01
Henagon

Re: Cannot connect to Teamviewer server since yesterday

I have not been able to connect on mobile network (tmobile)from phone for almost a month. Still no solution
Posted by pat7471
Henagon

Re: Cannot connect to Teamviewer server since yesterday

Cannot even ping the master server.

C:\>ping master1.teamviewer.com

Pinging master1.teamviewer.com [185.188.32.1] with 32 bytes of data:
General failure.
General failure.
General failure.
General failure.

Ping statistics for 185.188.32.1:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Posted by pwhittemore
Henagon

Re: Cannot connect to Teamviewer server since yesterday

I still have the issue at home.  If I bring my work laptop home it connects fine, so it's not network or ISP.  Something computer related.

I can login to TeamViewer via a broswer and that works fine, just not the stand alone app for some reason.

Any updates?

Posted by sh1t1985
Photon

Re: Cannot connect to Teamviewer server since yesterday

What is the exact thing to do with this? i have the same issue,, and i have a good connection, I'm using Win10.

Posted by despinamina
Photon

Re: Cannot connect to Teamviewer server since yesterday

it doesn't work in Greece

Posted by 925ADMIN
Henagon

Re: Cannot connect to Teamviewer server since yesterday

I have also been experiencing this issue since the weekend.

I get the error "Not ready. Please check your connection"

- It is occurring on both my Windows 7 laptop and my Macbook Pro.

- I have connected to multiple different networks (home/ work/ mobile hotspot), and the issue remains consistent.

- I have also tried uninstalling and reinstalling Teamviewer 11, the issue remains.

This is a real problem for us as we have a corporate license and can now no longer support our users.

Please advise.

Posted by TeamViewer Staff
TeamViewer Staff

Re: Cannot connect to Teamviewer server since yesterday

Dear @925ADMIN

Thank you for your post. After checking you request I notice that you have not a technical issue.

Could you please contact our salesteam directly here

Thank you in advance.

Best regards.
Reyhan

Did my reply answer your question? Please accept it as a solution to help others, Thanks.
Reyhan
Posted by jyotirmoy21
Henagon

Re: Cannot connect to Teamviewer server since yesterday

Yes, it connects now after running this command in bash.

Thank you very much.

Posted by jyotirmoy21
Henagon

Re: Cannot connect to Teamviewer server since yesterday

Thank you very much. Running the command in terminal, solve the problem. I think this may be due to firewall of the system. What do you think?

Posted by lellison
Electron

Re: Cannot connect to Teamviewer server since yesterday

Is there a solution to this problem. I have the same issue described in the above posts. Cannot connect to TeamViewer. In my case it works from one network/location, but the same laptop will not connect to TeamViewer from a second/different location.  The location that fails is a Comcast network. 

Posted by patdwhite
Photon

Re: Cannot connect to Teamviewer server since yesterday

I still see this issue:

Connect timed out to ping3.teamviewer.com:5938

Is there anything i can do?

Posted by gordioo_1
Photon

Re: Cannot connect to Teamviewer server since yesterday

I tried 

telnet master1.teamviewer.com 5938

Connecting To master1.teamviewer.com...Could not open connection to the host, on port 5938: Connect failed

Posted by lucshu
Photon

Re: Cannot connect to Teamviewer server since yesterday

"I am having same issue. Find below log from Teamviewer.

Not Ready: Please check you connection"

 

[personal information removed by moderator] 

How to get rid of it? I am suffering from last 5 days but not getting the viable solution. Also, it is working fine under wired connection but not in wireless.