You can submit or resubmit AutoSSL requests for a user with the following guide:
How to manually check the AutoSSL status of a single user
Although, if you find that the certificate has already been submitted and is still pending, you can use the following procedure to check the pending queue.
Issue the following command:
If there are pending certificates you will see those. If there are none, there will be no output.
If you must, you may also try the force option to force a new check: