I'm setting up civicrm-5.47.2-wordpress with wordpress-5.9.2 on Ubuntu 20.04 running Cyberpanel 2.1, on AWS Lightsail with AWS SES SMTP credentials in CiviCRM Outbound email where 'Save & Send Test Email' works. I can also send individual email to contacts.
But when I create a draft mailing and use 'Send test email to:' or 'Send test email to group', it tells me it is sent, but then I get the "Could not identify any recipients. Perhaps your test group is empty..." message. It also marks those contacts as 'On hold'. (But I can unset the 'On hold' and email individually from CiviCRM.)
There are no clues in ConfigAndLog.
I can't seem to debug this issue. Need some help please.