missing tables / Uncaught RuntimeException: Unable to claim actions. DB error

Replies: 2

I received a mailbot alert that the WP Mail SMTP plugin has started malfunctioning, and it appears it is missing database tables. One of the error messages I received in the WP Mail SMTP settings was to contact the developer.

An error of type E_ERROR was caused in line 683 of the file /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/data-stores/ActionScheduler_DBStore.php. Error message: Uncaught RuntimeException: Unable to claim actions. Database error. in /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/data-stores/ActionScheduler_DBStore.php:683
Stack trace:
#0 /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/data-stores/ActionScheduler_DBStore.php(597): ActionScheduler_DBStore->claim_actions(0, 25, NULL, Array, '')
#1 /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/data-stores/ActionScheduler_HybridStore.php(221): ActionScheduler_DBStore->stake_claim(25, NULL, Array, '')
#2 /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/ActionScheduler_QueueRunner.php(153): ActionScheduler_HybridStore->stake_claim(25)
#3 /wp-content/plugins/wp-mail-smtp/vendor/woocommerce/action-scheduler/classes/ActionScheduler_QueueRunner.php(132): ActionScheduler_QueueRunner->do_batch(25, 'WP Cron')
#4 /wp-includes/class-wp-hook.php(307): ActionScheduler_QueueRunner->run('WP Cron')
#5 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)
#6 /wp-includes/plugin.php(524): WP_Hook->do_action(Array)
#7 /wp-cron.php(138): do_action_ref_array('action_schedule...', Array)
#8 {main}
  thrown

this error shown on scheduled actions page

It appears one or more database tables were missing. Attempting to re-create the missing table(s).

this error on debug events page

Debug Events are Not Installed Correctly
The database table was not installed correctly. Please contact plugin support to diagnose and fix the issue. Provide them the error message below:

Unknown collation: 'utf8mb4_unicode'

This has been running for a few years without this issue. how can it be resolved?

Thanks