Snakemake version
6.7.0

Describe the bug
Snakemake gets stuck for at least 5 minutes, not submitting any jobs. Inspection of what's going on via htop showed 100% CPU for a command called cbc which seems to be a solver.

The next step involved selecting which of 1000 jobs to run, but they are all equivalent.

When I hit Ctrl+c Snakemake seemed to recover and printed that it switched to greedy solver:

Failed to solve scheduling problem with ILP solver in time (10s).
Falling back to greedy solver.

I read somewhere that usually that switch should happen after 10 seconds. In this case, that didn't happen.

The jobs were to be submitted on a SLURM cluster.

I'm not sure this is reproducible, but I thought I raise it anyways so that others who encounter similar issues can post below and know they're not alone.

Workaround
Hit Ctrl+C once

Hitting Ctrl+c manually works as a workaround