How to fix the issue of output file not appearing, after having launched a run configuration? - optimization

Question

I work on CVRP in combinatorial optimization, where the goal is to compare several models on several instances, using the OPL language. For this to e done, I first wrote and tested the said models; then I wrote an main flow control supposed to run each instance for a 2 hours duration.
My problem is that after 2 hours, and this for each model, the output file appears for some instances, containing the desired information; but for other instances, the output files do not appear, as if these instances do not exist. This problem persists even when you launch one or more of these instances in isolation.
below is the main flow control code, where BPF designates the name of the .mod file, which is simply modified in the code, when one wishes to switch to another model.
{string} datFiles=...;
main {
var source = new IloOplModelSource("BPF.mod");
var cplex = new IloCplex();
var def = new IloOplModelDefinition(source);
cplex.tilim=2*60*60;
cplex.threads=1;
for(var datFile in thisOplModel.datFiles)
{
var opl = new IloOplModel(def,cplex);
var data2= new IloOplDataSource(datFile);
opl.addDataSource(data2);
opl.generate();
var o=new IloOplOutputFile("BPF "+datFile+".txt");
if (cplex.solve()) {
if(cplex.getCplexStatus()==11){
o.writeln("instance : " + datFile
+" / opt = "
+ " / UB = " + cplex.getObjValue()
+ " / LB = " + cplex.getBestObjValue()
+" / time = " + " - "
+" / Gap = "+cplex.getMIPRelativeGap()*100+"%");
}
else {
o.writeln("instance : " + datFile
+ " / opt = " + cplex.getObjValue()
+ " / UB = " + cplex.getBestObjValue()+"*"
+" / time = " + cplex.getSolvedTime()
+ " / Gap : -");
}
o.close();
}
opl.end();
}
}