Database Doesn’t exist database error with ig_queue

Ongoing problem with this error in my error.log file. This is a multisite system, PHP 7.3.15, WP 5.3.2 (although an ongoing problem with prior versions), Email Subscibers latest verion (updated today). (Changed the database name to [wp_database].

Error message appears to be from Email Subscibers plugin, based on the ‘ig_*’ in the query.

[12-Mar-2020 21:12:05 UTC] WordPress database error Table '[wp_database].wp_apkp_37_ig_queue' doesn't exist for query 
SELECT queue.campaign_id, 
 queue.contact_id, queue.count AS _count, queue.requeued AS _requeued, 
queue.options  
AS _options, queue.tags AS _tags, queue.priority AS _priority 
FROM wp_apkp_37_ig_queue 
 AS queue LEFT JOIN wp_apkp_37_ig_campaigns AS campaigns ON 
campaigns.id = queue.campaign_id WHERE queue.timestamp <= 1584047525 
AND queue.sent_at = 0 AND (campaigns.status = 1) 
ORDER BY queue.priority DESC made by 
do_action_ref_array('ig_es_cron_worker'), WP_Hook->do_action, 
WP_Hook->apply_filters, ES_Queue->process_queue

What is causing this?

Thanks.