Thanks Brogan here it is. If I'm reading things correctly...looks like it may be related to a 3rd party add-on. If you can help great...or I can contact the add-on developer.
Thanks
#0 src/addons/Andy/LinkCheck/XF/Cron/LinkCheck.php(42): XF\Error->logError('Email to userna...')
#1 [internal function]: Andy\LinkCheck\XF\Cron\LinkCheck::runLinkCheck(Object(XF\Entity\CronEntry))
#2 src/XF/Job/Cron.php(34): call_user_func(Array, Object(XF\Entity\CronEntry))
#3 src/XF/Job/Manager.php(253): XF\Job\Cron->run(G)
#4 src/XF/Job/Manager.php(195): XF\Job\Manager->runJobInternal(Array, G)
#5 src/XF/Job/Manager.php(79): XF\Job\Manager->runJobEntry(Array, G)
#6 job.php(42): XF\Job\Manager->runQueue(false, 8)
#7 {main}