Unable to run parpool in Net application. Failed to initialize the interactive session.

I have an initialization routine in my .Net compiled MatlabAlgo dll.

 poolobj = gcp('nocreate'); % If no pool, do not create new one.
 if isempty(poolobj)
     poolobj = parpool( 'local','IdleTimeout', 240);
 end

I run this from a thread in my C# application.

I get the following error:

Parallel pool failed to start with the following error.

Failed to initialize the interactive session.

C:\Program Files\MATLAB\R2021b\mcr\toolbox\parallel\cluster\parpool.m, name parpool, line 146.

Version R2021b

Windows 11

.NET

[Sam Marshalik]

Can you verify that you are able to run MATLAB on that machine and open a parpool (with the above commands) in that MATLAB session?

[Hans Dohse]

Yes I have no problem running it from Matlab.