Dear Guusje,

I am reposting our response from support, to make this information visible to others. Thank you @dsalakirova !

The settings you can find the following way:
1. In the logs of the session you see a line containing "Using PRO-Worker license profile 'ClientOnServer' -> this means that the project was uploaded with this license profile. This is one of the so -called Worker profiles as visible in the PRO Configurator (accessible as shown below):

2. Open the License Manager on the PRO Server machine: 

You will see all the licenses PRO uses. 

You will see the Profiles in the Profile Column. 

Find the license with profile name "ClientOnServer".
This should be the license currently in use by the session. To see its details click Maintenance/Maintenance mode, then Maintenance/License/License configuration

You will see all the licenses. Find the one that belongs to the "ClientOnServer" profile and see which are the allowed solvers. 

Is the one you use locally one of them?

Hi, thank you for the response! 

I looked up our licenses, for the ‘ClientOnServer’ license there is indeed no allowed solver. However, we do have a ‘server’ license with a CPLEX solver. This worked before and we did not make any changes in the code. In addition, for another application on the same PRO environment, the optimization does work.

Locally, I’m using another license, so I do not think this is related.

This was resolved by reviewing the worker profile that was being selected for the app that was being published. When you publish an app and you have multiple worker profiles configured, you may select one that is different from the default one. Apparently, the additional one does not have solvers available to run, hence they were unable to use it.

You must also be careful when using the DelegateToServer procedure, since you can also change the worker profile that is being used.