Hello Karima,
Error: CalledProcessError:
Command 'b'./simfactory/bin/sim build -j2 --thornlist ../einsteintoolkit.th\n'' returned non-zero exit status 2.
This looks to me as if python3 was used to run sim.py.
However Simfactory (certainly in the Sommerfeld release) only supports Python2.
Can you run:
bash -x ./simfactory/bin/sim &>sim.log
and send the file sim.log, please? This would should which version of python is used.
Yours, Roland