Learning Forum

[Mathieu G]

Hi,

I have recently installed Ansys 2024R1 and since, I regularly have the error "FLUENT failed to validate the connection" from workbench.
Fluent is running fine until the following message appears in the console :

 from 127.0.0.1 on port 51260
[...]
 from 127.0.0.1 on port 51391
[mpiexec@j5023-12] HYD_dmx_wait_for_event (..\windows\src\hydra_demux.c:231): unable to post next accept
[mpiexec@j5023-12] wmain (mpiexec.c:2086): error waiting for event
 Error in the fluent (fl) process : ended abnormally

Fluent is automatically closed. And if I try to reopen it, the "FLUENT failed to validate the connection" appears. Closing Workbench and reopen it fixes the issue for a few hours.

I already tried most of the solutions proposed on the forums. Could this be linked to having 2023R2 and 2024R1 installed at the same time ?

Thanks,

[Rob]

It'll not be linked to having two versions installed or Ansys staff would have noticed it: we typically have 5-6 versions of Fluent! Does the same thing happen if you run Fluent outside of Workbench? 

[Mathieu G]

Yes it's happening when running standalone Fluent. That's where I captured the console message

[Gary_S]

 

I have a similar issue but with the Ansys MAPDL solver on 23.1. 

A workaround for MAPDL for now has been to specify an alternate MPI. 

So, see if Fluent has a way to specify an alternate MPI, say an eariler Intel MPI or msmpi or openmpi. 

 

[Rob]

There are options in the Fluent launcher, and I've asked one of the installation team to have a look. 

[George Karnos]

Try the following:
In the Fluent Launcher in the tab “Parallel Settings” set MPI Types = msmpi Select IP Interface = 127.0.0.1 in which 127.0.0.1 is your local machine.

[Mathieu G]

Thanks for your assistance ! I'll switch up the MPI type and IP interface and let you know how it goes.

[Gary_S]

Hi Mathieu

Just following up. Were you able to run successfully with the alternate MPI?

[Mathieu G]

Hi! Yes, the error didn't reappear when using the alternate MPI, even during very long calculations.

Thank you for your help!

[Gary_S]

Hi Mathieu

 If you are a commercial Ansys customer, I would like you to create a formal support case so that we
 may collect additional system information that can help us undersand the cause of the issue. 
Thanks!

Gary

[Mathieu G]

Hi,

I'm using an academic license provided by my university

[Gary_S]

OK

Can you look in this folder and tell me if there are any DLLs that start with umppc ?

C:\Windows\System32\umppc*****.dll 
(Your folder view settings might need changed to allow you to see system files / file extensions)

Gary

[Mathieu G]

Sure, only one : umppc18207.dll

[Gary_S]

Hi Mathieu

 Thank you very much for confirming. 

umppc*****.dll (s) are part of an Endpoint Protection Program 

It appears this Endpoint Protection Program causes isues with MPI (Parallel processing).

We have reports that it causes problem such as slowdowns or crashes in the Ansys and Fluent parallel solvers. 

You may want to report this issue to your IT department. 

Gary

[Mathieu G]

Hi,

Thank you for the detailled explanation ! I'll look into it with my IT departement.

[Gary_S]

Does your university run the Ansys / Fluent products on Linux? 
If so, it may be useful to see if the same failure issue occurs on the Linux platform too.

Also, does your site use Rapid7 Insight agent?