Nprinting web console not working

[ops_team]

I received an email notification on 27^th Dec on the Nprinting task (see text within the underlined section).

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Qlik NPrinting task ran with 1 error.

Task: Cache generation task for connection ADU App Connection

Started: 12/27/2021 6:55:00 AM

Finished: 12/27/2021 6:55:20 PM

Errors

12/27/2021 6:55:22 PM Error     Cache generation timed out

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On going to the services and restarting NPrinting services as per the following post - https://community.qlik.com/t5/Knowledge/Proper-Order-to-Restart-Qlik-NPrinting-Services/ta-p/1715333 , I am able to access the Nprinting web console but on clicking on Connections, the webpage is still running (see screenshot below).

I checked the Nprinting engine log - "C:\ProgramData\NPrinting\Logs\nprinting_engine.log" and noticed the following message ‘RabbitMq bus is not connected - trying listener registration again in 10 seconds’.

The Qlik Nprinting engine version is 19.9.5.0. This issue has happened for the first time.

Please assist as soon as possible.

Thanks,

OPS

[ops_team]

Greetings,

In addition to the above issue, when I tried restarting the Nprinting scheduler, I was getting these two messages on each attempt to stop the service and then finally I had to go to Task Manager to stop the services there for scheduler only.

Thanks,

OPS

[Lech_Miszkiewicz]

Restart OS and check again.

cheers

Lech

[ops_team]

Dear Lech

You mean restart the server?

[Lech_Miszkiewicz]

yes. have you done that already?

The fact that services are stuck or not working would mean that you would have to kill individual tasks and processes first. The easiest solution is then to restart server and see if the issue is still there.

cheers

[ops_team]

Hi Lech

I just did that but on accessing the web console, when I go to Task Executions, I see the cache generation showing ongoing with no percentage of completion and all the tasks which were executed on 28th Dec but not completed still active. When I try to abort them, I get an error message that it is not possible to abort. Do you know why?

Thanks,

OPS

[Lech_Miszkiewicz]

Not sure what error you talk about... so yeah - hard to advice on that.

The fact that outstanding tasks kicked in is normal, so if you were to cancel them I would first disable all apps in NPrinting and do secondary restart of the server. That way they should be skipped after restart and you can start more investigation.

Obviously it is hard to say more as we don;t know why your NPrinting simply does not finish running tasks. There might be more to it like:

• limited resources
• limited disk space on C drive
• missing service account privileges
• and many more...

You typically start investigating from the first point of failure by investigating day and time of failure and checking all logs from NPrinting server including all services logs. Once you do that you normally would see what was the cause of the problem in first place. 

At the moment I cannot advice more as there is not enough details on what is wrong. The only thing we  know is that your report stopped working and they not proceeding.

[ops_team]

Dear Lech,

I received a notification via email that a Qlik Nprinting task ran with 1 error. The name of my connection is ADU App Connection and it started at 6:55 AM and finished only after 12 hours. The cache generation timed out. 

Task: Cache generation task for connection ADU App Connection

Started: 12/27/2021 6:55:00 AM

Finished: 12/27/2021 6:55:20 PM

Errors

12/27/2021 6:55:22 PM Error     Cache generation timed out

On 28th Dec, I as usual restarted all the nprinting services via the Task Service and noticed that the Nprinting scheduler is not stopping. So, for this to stop, I terminated the task in the Task Manager. On restarting the nprinting services, I could login to Nprinting web console but when I checked the task status tab, I saw many tasks of 28th Dec still running with 0% completion. I tried aborting them but not successful. 

Today, I restarted the server, all Qlik and Nprinting services and easily logged into Nprinting web console and noticed that the tasks scheduled on 28th Dec are still running with no % of completion and unable to abort them. Then when I click on Connections, it keeps running without showing my connections list. See the screenshot Connections attached. 

There is no issue with the server or disk space. There is a cache generation issue and I am unable to abort the tasks currently appearing as running in Nprinting web console. 

When I checked the Nprinting Scheduler log of 28th Dec, I noticed the following error 'RabbitMq service is not connected - trying again in 60 seconds' and then towards the end I saw the following FATAL error (see bold italicized text below and attached screenshot of the latest 28th Dec log details.

Fatal error on Scheduler service. ERROR: System.NullReferenceException: Object reference not set to an instance of an object.↓↓ at Qlik.NPrinting.Scheduler.Service.LoadBalancer.Dispose() in C:\Jws\release-19.9.x-GsL0YuxYW\server\NPrinting\src\Scheduler\Service\LoadBalancer.cs:line 122↓↓ at Autofac.Core.Disposer.Dispose(Boolean disposing)↓↓ at Autofac.Util.Disposable.Dispose()↓↓ at Autofac.Core.Lifetime.LifetimeScope.Dispose(Boolean disposing)↓↓ at Autofac.Util.Disposable.Dispose()↓↓ at Autofac.Core.Container.Dispose(Boolean disposing)↓↓ at Autofac.Util.Disposable.Dispose()↓↓ at Topshelf.ServiceConfiguratorExtensions.<>c__DisplayClass3_0`1.<WhenStopped>b__0(T service, HostControl control)↓↓ at Topshelf.Builders.DelegateServiceBuilder`1.DelegateServiceHandle.Stop(HostControl hostControl)↓↓ at Topshelf.Runtime.Windows.WindowsServiceHost.OnStop()

Please help!

Thanks,

OPS

[Lech_Miszkiewicz · Accepted solution]

hi, 

There is not enough information and frankly in this case I would probably open support ticket or get someone who is experienced in NPrinting (like qlik partner) to have a look at it for you. The fact that you cannot see connections or that some services dont work correctly or dont communicate correctly indicates to me that there could be larger problem. 

Doing it via community is too cumbersome. 

What you are showing is very confusing and there may be a lot at risk - repository. Iu hope you take regular backups of the server (if not the snapshot of whole instance then at least regular backup of repository).  Trying to solve this on community might not be a good idea as you will not be able to share all the information - like all logs, not just part of scheduler logs. Like i said - investigating all logs from NPrinting server would be critical starting point. That would include looking at windows event viewer as well. If at some stage something has changed we must know what was it. 

but if you still want to go ahead and try things you might as well try to see why you get RabbitMq error and follow steps from https://help.qlik.com to try to troubleshoot it:

https://help.qlik.com/en-US/nprinting/May2021/Content/NPrinting/Troubleshooting/Qlik-NPrinting-Messa...

cheers

[Frank_S]

Hello @ops_team

Lech is 100% correct...this is an issue that is worth of a Qlik Support request.

In any case, the error you reported copied below is the very issue that is resolved by following the steps in the help link which Lech has already provided you with:

• ‘RabbitMq bus is not connected - trying listener registration again in 10 seconds’.

And since you are running a version of NPrinting that is out of the support cycle NP 19.9.5.0 (April 2019), I would urge you to upgrade as soon as possible to not only get back onto a supported platform but also to resolve the issue you are reporting. Upgrading should fix your damaged messaging and scheduler services.

Kind regards...

ps: It's very important to send questions here in the community discussion pages rather than Private Messages. This so that all community members have the opportunity to share possible solutions or sharing in the solutions provided.