Desktop Client cannot connect to server

Submitted by toni.ann on 2013-01-04

Hello, i am having a problem with the desktop client application, upon connection it says "Connection could not be opened. Server returned an invalid response."
We can connect using the browser though. The desktop client worked fine last week and we did not change any setting on our server nor did any upgrade. Any ideas?

Thanks,
Toni

Are there any errors in the server's event log?

Regards,
Michał

There were no entries in the server error log. I also tried to reinstall the desktop client application but it is still not working. The portable version also does not work.

myself and my whole team is having exactly the same problem, since we have tried to access it in 2013 all of a sudden no one can user the desktop client.

Same for us, no changes were made on the server and the log shows no errors.

I have played and tried everything i could think of but can not resolve the problem which is a real pain because we get all our reports out of the desktop client :(

Thanks Louise

Well, that's actually an indication that it's working correctly :).

Could you try to debug the communication between the client and the server, for example using something like fiddler?

Regards,
Michał

I don't know if this is what you mean by debugging but here's what i got:

Request Header:

POST /server/webissues/handler.php HTTP/1.1
Content-Type: multipart/form-data; boundary=nextPart-9nqAJct2AC1f
Content-Length: 109
Connection: Keep-Alive
Accept-Encoding: gzip
Accept-Language: en-US,*
User-Agent: Mozilla/5.0
Host: issues.cyberfrontierpos.com

Response Header:
HTTP/1.1 406 Not Acceptable
Date: Mon, 14 Jan 2013 01:34:27 GMT
Server: Apache
Content-Length: 226
Keep-Alive: timeout=5, max=75
Connection: Keep-Alive
Content-Type: text/html; charset=iso-8859-1

Hi

I tried what was suggested in that post but with no luck, still get the same error trying to connect.

I will contact my hosting though to see if they have enabled any new security that was not on there last year. It does seem strange that it worked perfectly last year, it is only since it ticked over to 2013 that it has stopped working.

Thanks
Louise

If there is a version mismatch, there is a different error message.

By the way, I'm going to fix the error caused by mod_security in the next version of the desktop client. It turns out that it's enough to add the 'Accept' header to the request, even though it's not strictly required by the HTTP standard.

Regards,
Michał

Dear Michał,

i also had same issue "Connection could not be opened. Server returned an invalid response." under desktop client less the year ago. I just deleted and forget your software due did found the solution.
After one year i returned and found the same problem after install.
So it would be great that you hear your users that they have problem and post the solution.
I found that ".htaccess" in /webissues/server/webissues directory with 

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

<IfModule mod_security2.c>
SecRuleEngine Off
</IfModule>

solve this problem.

In version 1.0.5 I added the Accept header to WI requests, which may circumvent some false warnings caused by mod_security. However, mod_security can be configured in a lot of ways, and it's simply impossible to predict and fix all the problem that it can cause. Because of that, disabling it is indeed the recommended solution. Your hint is very good, I will add it to the next version of the documentation.

Regards,
Michał