Connection disconnected fequently

[陈鹏鹏 <st...@gmail.com>]

Hi,

I’m building a web app based on guacamole 1.4.0 and users report connection disconnected frequently.  
I found that when this occurs, the tunnel status code is 519(0x207) which throws by GuacamoleUpstreamNotFoundException, the guacd log says ‘User is not responding’ as bellow:

Mar 30 13:32:58 localhost guacd[3884630]: User "@25878c10-2d03-41e9-9037-978ef4fde75e" joined connection "$db89b7f3-952a-41ef-bf3f-a4f43b53a7ee" (1 users now present)
Mar 30 13:32:58 localhost guacd[3884630]: Client is using protocol version "VERSION_1_3_0"
Mar 30 13:32:58 localhost guacd[3884630]: Using non-standard VNC clipboard encoding: 'UTF-8'.
Mar 30 13:32:58 localhost guacd[3884630]: VNC server supports protocol version 3.7 (viewer 3.8)
Mar 30 13:32:58 localhost guacd[3884630]: We have 1 security types to read
Mar 30 13:32:58 localhost guacd[3884630]: 0) Received security type 18
Mar 30 13:32:58 localhost guacd[3884630]: Selecting security type 18 (0/1 in the list)
Mar 30 13:32:58 localhost guacd[3884630]: Selected Security Scheme 18
Mar 30 13:32:58 localhost guacd[3884630]: GnuTLS version 3.7.3 initialized.
Mar 30 13:32:58 localhost guacd[3884630]: TLS session initialized.
Mar 30 13:32:58 localhost guacd[3884630]: TLS anonymous credential created.
Mar 30 13:32:58 localhost guacd[3884630]: TLS handshake blocking.
Mar 30 13:32:59 localhost guacd[3884630]: TLS handshake blocking.
Mar 30 13:33:00 localhost guacd[3884630]: TLS handshake done.
Mar 30 13:33:00 localhost guacd[3884630]: We have 1 security types to read
Mar 30 13:33:00 localhost guacd[3884630]: 0) Received security type 2
Mar 30 13:33:00 localhost guacd[3884630]: Selecting security type 2 (0/1 in the list)
Mar 30 13:33:00 localhost guacd[3884630]: Libgcrypt warning: missing initialization - please fix the application
Mar 30 13:33:00 localhost guacd[3884630]: VNC authentication succeeded
Mar 30 13:33:00 localhost guacd[3884630]: Desktop name "jenkins@SQE-ATT-NT2-CN-157"
Mar 30 13:33:00 localhost guacd[3884630]: Connected to VNC server, using protocol version 3.7
Mar 30 13:33:00 localhost guacd[3884630]: VNC server default format:
Mar 30 13:33:00 localhost guacd[3884630]:   32 bits per pixel.
Mar 30 13:33:00 localhost guacd[3884630]:   Least significant byte first in each pixel.
Mar 30 13:33:00 localhost guacd[3884630]:   TRUE colour: max red 255 green 255 blue 255, shift red 16 green 8 blue 0
Mar 30 13:33:51 localhost guacd[3884630]: User is not responding.
Mar 30 13:33:51 localhost guacd[3884630]: User "@25878c10-2d03-41e9-9037-978ef4fde75e" disconnected (0 users remain)
Mar 30 13:33:51 localhost guacd[3884630]: Last user of connection "$db89b7f3-952a-41ef-bf3f-a4f43b53a7ee" disconnected
Mar 30 13:33:51 localhost guacd[3884630]: Requesting termination of client...
Mar 30 13:33:51 localhost guacd[3884630]: Internal VNC client disconnected
Mar 30 13:33:51 localhost guacd[3884630]: Client terminated successfully.

I want to know the reason of this error and how to avoid this. I guess bad network will cause this but not sure. Do you have any ideas about this? Thanks a lot.