Embedded Qlik sheets via iframe gives error intermittently

[Udo]

Hi all,

When viewing embedded Qlik sheets on an internal web site, users are reporting that they receive intermittently "400 - Bad Request" errors or receive an error that the Qlik Sense engine wasn't found".

We found the below article and changed the proxy config accordingly ( https://support.qlik.com/articles/000098524).
Since we are running Qlik Sense for Windows June 2020 version, we thought this bug should not appear.
Anyway, changing the proxy config, did not help getting this resolved.

Do you have some hints, where to look at to resolve this problem?

Thanks,
Udo

js console error

Error message in browser

[Damien_V]

Hello @Udo 

The error seems slightly different than the one in the KB article.

Could you provide a bit more details on how is the environment set up ? Is there any load balancers/reverse proxy/gateways/forward proxy between end users and the Qlik Sense server.

Also, does it just work again by refreshing the page ? or does it persist ?
It could ever be a drop of connection for the websocket connection (which could potentially be mitigated with https://community.qlik.com/t5/Knowledge-Base/Enabling-TCP-Keep-Alive-Functionality-In-Qlik-Sense/ta-...)

or maybe it's the Qlik Engine crashing on the Qlik Sense server, which you could verify by checking the logs in C:\programdata\qlik\sense\log\engine for that specific timestamp.

[Udo]

Hello @Damien_V ,

Thanks for your reply! We are running a multi server environment. There are two scheduler servers (one being the master node) and two for consumer access. The two consumer nodes are loadbalanced via a network loadbalancer.
Refreshing the page would not resolve this. Users say, they need to go to the Qlik hub, sign out, sign back in. After that the embedded site would work on refresh. In the log files I don't see any errors which would indicate the engine crashing.
Thanks!

[Udo]

@Damien_V  We just upgraded to February 2021 Patch 4 and still see this issue.
Do you have any idea what we could try to get this problem solved?
Should we create an official support ticket?

Thanks!