Using /code in Hipchat room gives spurious Couldn't send error message

[tmcti]

Running: Hipchat Client v4.29.0.732 on Mac OS X.

In a Hipchat room, if I use /code to send something preformatted, I get the error message:

"Couldn't send  Retry    Cancel"  with my code block highlighted.

If I click resend, it sends it a second time to the channel and so it shows up twice.

If I click away from the room and back again, the message goes away and the code block is sent properly to the channel.

Is this a bug in the client?

[AnnWorley]

I use the /code feature on my Mac without seeing that issue. Does it matter which code you send? Does it do the same thing if you just type "some code"?

The HipChat support team wants to know whether you are using a local HipChat server or the Cloud HipChat because:

"When you send a command to HipChat, HipChat actually sends a notification back to your client to let it know the message was delivered. When that mechanism breaks, you see the error they're referring to. For that reason, the server-side implementation is relevant here."

[tmcti]

Hi,

  I think it's when multiple lines are sent after the /code. I will do some tests and see at which length it happens.

[tmcti]

I can't seem to reproduce it now. I'm connecting to the cloud hipchat server, but I am also VPN'd into work so my hipchat goes:

My Mac -> Work VPN -> Out of work's gateway

I just tested with the Work VPN and couldn't reproduce. It seems to happen during the day (GMT+1). I'll have to see if I can do tcpdumps of the packets to see if it's a TCP transmission error to the server or something.

[AnnWorley]

Interesting - do keep us posted. :)

[tmcti]

OK the problem happens in the office, too, with a stable wifi connection and fairly big pipe out to the internet.

Does the Atlassian Hipchat server throttle multiple connections from a single IP?
Reason I ask is we have quite a few people connecting from behind NAT. (about 55-60)

[tmcti]

Is PMTU discovery allowed to the Atlassian Hipchat server?

(Should be ICMP Type 3 code 4)
Looks like standard ping isn't working, so ICMP might be blocked.

I'm guessing since you are hosting the Atlassian Hipchat server on AWS, you could ask your I.T. team if ICMP Destination Unreachable is allowed in/out (which is perfectly safe)

More information here: https://en.wikipedia.org/wiki/Path_MTU_Discovery

[tmcti]

From http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/network_mtu.html#path_mtu_discovery :

"

Path MTU Discovery is used to determine the path MTU between two devices. The path MTU is the maximum packet size that's supported on the path between the originating host and the receiving host. If a host sends a packet that's larger than the MTU of the receiving host or that's larger than the MTU of a device along the path, the receiving host or device returns the following ICMP message: Destination Unreachable: Fragmentation Needed and Don't Fragment was Set (Type 3, Code 4). This instructs the original host to adjust the MTU until the packet can be transmitted.

By default, security groups do not allow any inbound ICMP traffic. To ensure that your instance can receive this message and the packet does not get dropped, you must add a Custom ICMP Rule with the Destination Unreachable protocol to the inbound security group rules for your instance."