Users Experiencing Frequent "An error occurred. Connection lost" Messages - Qlik Sense

[matthewharrison]

It has been raised to our attention that some users have been experiencing frequent Qlik Sense timeouts with the message of:

"An error occurred - Connection lost.  Make sure that Qlik Sense in running properly.  If your session has timed out due to inactivity, refresh to continue working. "

Users claim that it is taking just a couple minutes to timeout on a Qlik report, and even when they are actively using it, not only when inactive.  We have also experienced this issue ourselves as admins, with reports giving connection error messages while we are using them.  When not using them, the connection error will always appear within 5 minutes or so.

After checking our proxies and networking settings in QMC, we can't find any settings which would indicate this, and inactivity timeouts are set to 15+ minutes so that is not it either.  The underlying infrastructure running our Qlik server has has zero unscheduled downtime and does not involve and complex networking infrastructure - only an app service plan in Azure. Has anyone else experienced something like this?

[Jay_Brown]

Hello @matthewharrison , what's the full version that you are seeing this on?

[matthewharrison]

We are currently running Qlik Sense Server version 14.67.11 (May 2022 Patch 2).

Also We have observed the issue becoming more prevalent with timeouts even for the admins happening in about 4-5 minutes, so we know this is not an issue of republishing apps.

[Jay_Brown · Accepted solution]

Hi Matthew, thanks for the update.

Based on the 4-5 minute description this sounds as if it is an issue with sticky sessions.

Please see the following:
https://community.qlik.com/t5/Deployment-Management/Session-Timeout-Connection-Lost/td-p/1548837
https://community.qlik.com/t5/Integration-Extension-APIs/Set-up-for-Multinode-site-avoiding-session-...
https://community.qlik.com/t5/Official-Support-Articles/Network-Load-Balancer-NLB-Requirements-for-Q...
https://community.qlik.com/t5/Official-Support-Articles/How-to-configure-Network-Loadbalancer-NLB-wi...

Please check with your internal network teams to check the session configuration on any network load balancers, it is very common for these to be set at 5 minutes (default on some vendors) and as Sense requires persistent sessions, you'll see this error.

Thank you!