The following solution resolves this issue:
I have the following warning in the Python console, though.
Warning: Did not find environment variable ACADOS_SOURCE_DIR, guessed ACADOS_PATH to be /Users/acados.
Please export ACADOS_SOURCE_DIR to avoid this warning.
And also this:
acados was compiled without OpenMP.
I know that these may not all be relevant for the current issue, they are posted here mainly for my future reference.
Thank you all for the help!