Similar to CiviRules triggers, but fails to send email, but I've not seen a resolution there. For the past ~year, have had CiviRules sending my DRIP email campaign, along with a couple of tag setting functions.
(techie enough to be dangerous... I can get in to things, but...)
Recently, (not sure exactly when) I noticed that it wasn't sending the emails, though, it was processing other things in the actions. Emails do send no problem - manually.
I didn't know about CiviRules logging, so just loaded it, but don't know where the logs might show up. I added another user, it triggered, but no emails, and no errors - at least not seen in Administer> Administration Console> View Log.
From above post, I saw about civicrm_queue_item table. There are a number of items there from the past ~2 months, but I don't know how to interpret.
Cron is running, including process civirules and process delayed civirule actions (both always, with no errors).
I just saw another question with problem with delays, so I changed the delay on my first email from 1minute - to no delay. Created user, with the trigger tag. It sent the email! Now, will it send the rest? (2, 4, 6... day delays on them.
Running: WordPress 5.5 CiviCRM 5.27.3 CiviRules 2.16 Email API 1.19
Thanks for any ideas/suggestions/hints... ..clark