Hi Tian,
If you are running version 9.21.0 it may be wise to upgrade to the LTS version. There were several fixes involving the task queue afaik.
I hope this helps.
Michiel
In addition to the other answers, I'd recommend installing the Task Queue Helper module from the Marketplace. I've found it really useful to see what is going on with my queues.
https://marketplace.mendix.com/link/component/117272
Good luck!
Hi Tian,
Did you take a look at the ProcessedQueueTask and QueuedTask tables in the System module? They might provide you more information on whether the task was actually put in the queue.
If they cannot be found there I suggest taking a look at the Mendix logging by for example checking the Message table from the Logging marketplace module to get more insight on what happened in your microflow.
Good luck on debugging.
Kind regards,
Mark