Error "Concurrent connections limit exceeded" After Upgrading to NPrinting February 2025 SR1

[iffahjo]

Hi All,

After upgrading Qlik NPrinting from September 2019 to February 2025 SR1, we encountered an issue where reports are not sent to some user emails. The tasks run successfully, but some emails fail to deliver with the following error message:

20250714065008 Error Failed to send email for user 'XXXXXXX' {XXXX-XXXX-XXXX-XXXX-XXXX}. ERROR: 4.3.2 Concurrent connections limit exceeded. Visit https://aka.ms/concurrent_sending for more information. [Hostname=server.outlook.com]

Previously on NPrinting September 2019, all reports were sent without any issues.

We have contacted support and already tried adjusting the following parameters in the scheduler.config file as suggested in the release notes:

• max-mail-client-connection-attempts: (default is 2)

• mail-client-connection-attempts-delay-ms: (default is 500 ms)

Reference: https://community.qlik.com/t5/Release-Notes/Qlik-NPrinting-Release-notes-February-2024-Service-Relea... 

Despite these changes, the problem persists. We’re unable to ask the SMTP admin to change server-side settings, especially since everything worked fine before the upgrade.

Has anyone else experienced this issue after upgrading? Any advice or workarounds would be greatly appreciated.

Thanks

[Ruggero_Piccoli · Accepted solution]

Hi,

Qlik NPrinting September 2019 and February 2025 SR1 manage the SMTP connections in the same way so I suppose February 2025 SR1 is installed in a new more powerful server able to create reports faster and this is reaching the SMTP limits. 

As workaround you could try to split the publish task into different ones and wait the end of the previous to run another. There is not a feature to limit the number of connections opened in a certain amount of time to the SMTP server. 

Best Regards,

Ruggero

[Frank_S]

Please also remember that the NPrinting server is NOT an email server. It acts like any other email client when sending reports. If you performed the same volume from any other email client, like outlook or gmail to your email server, you would likely encounter similar behavior.

If your email server that receives Nprinting emailed reports cannot handle the email volume sent to your email server, then you likely need to follow Ruggero's recommendation.

NPrinting server will send whatever you tell it to send...however your email server needs to be managed to handle the volume from the NP server. Alternatively, you may create more publish tasks scheduled at different times to mitigate the load to your email server.

Rather than for example: "all departments at 12 pm", consider the following.

• task 1 dept 1 task filter at 12 pm
• task 2 dept 2 task filter at 12:15 pm
• task 3 dept 3 task filter at 12:30 pm
• etc.

Kind regards...

[JavierL]

Hello, as user of Sense, Nprinting and Alerting, our systems team says there smtp server cannot be changed and we are facing this same issue, some users sometimes not receiving their emails because of the max concurrent connections, splitting the publish task would leave us with a few hundred of them, which is not an option for obvious reasons, we just found out qlik alerting has a file which specifies max concurrent conexions to email server, could you please confirm there is not such a thing in Nprinting nor any other workaround to throttle it?

[mbuquerasr]

Hola, 

Nosotros igual, tenemos Qlik Sense i al actualizar el Qlik NPrinting February 2025, nos da error en el envio de de los informes, ERROR: 4.3.2 Concurrent connections limit exceeded.

Para nosotros , no seria factible hacer múltiples tascas de una tasca, hay alguna otra alternativa? 

O alguna configuración para aumentar ese limite?

Gracias.

[JavierL]

Ante la falta de respuesta por parte de Qlik nos hemos buscado la vida, hemos optado por modificar el RabbitMQ que usa Qlik Nprinting por debajo para el envío, aún no hemos tenido tiempo de probarlo adecuadamente, a principios de mes cuando se lancen las tareas saldremos de dudas 

https://www.rabbitmq.com/docs/user-limits

[Ruggero_Piccoli]

Hi,

Next service releases, February 2025 SR3 and February 2024 SR7, will deliver some improvements on the SMTP management. 

You can implement undocumented settings but at your own risk. 

Best Regards,

Ruggero

[JavierL]

Thanks, good to know about the upcoming features anyway i will update if our workaround works as intended in the mean time  for those who cant/wont upgrade yet 

[mbuquerasr]

Hola,

Nosotros al final, hemos solucionado el problema con un servisor de relay.
Tenemos un servidor SMTP de relay, lo que nos evitar las restricciones de conexiones concurrentes.
Desde la implementación, los informes se envían correctamente sin errores de conexión.

Saludos,

[michael123]

Did the new SR solve the issue?

Did an upgrade a month ago on the same server (with the same jobs running after) where there wasn't any issues before. Tried adjusting the parameters as suggested above but with no improvement,