Task do not run in parallel I might not understand the parallel execution well. I have two tasks that are not demanded on each other, when I trigger the flow manually, one task runs and the other is pending (when looking at the UI flow run schematic). the code looks like

from datetime import timedelta
from prefect import task, Flow
from prefect.schedules import CronSchedule
from time import sleep


@task(max_retries=1, retry_delay=timedelta(minutes=10), timeout=2000)
def tast_1():
    sleep(10)
    print('Do task 1')
    return True


@task(max_retries=1, retry_delay=timedelta(minutes=10), timeout=2000)
def tast_2():
    sleep(10)
    print('Do task 2')
    return True


def main():
    schedule = CronSchedule("0 15 * * *")

    with Flow("parallel tasks", schedule=schedule) as flow:
        r1 = tast_1()
        r2 = tast_2()

    flow.register(project_name="parallel tasks")


if __name__ == "__main__":
    main()

What executor are you using? I am not sure what the default is, but the following should enable parallel task execution:

from prefect.executors import LocalDaskExecutor

...

with Flow("parallel tasks", schedule=schedule, executor=LocalDaskExecutor()) as flow:

Thanks, that solved the issue

The default is a LocalExecutor which is just single threaded and sequential execution.