CiviRules send email not working

We have a couple rule setup to email new contacts. Those emails have stopped going out recently. I setup a basic rule to test and received an smtp authentication error. The site is setup to use mail() method for sending email and other emails are going out find. It seems CiviRules is attempting to send via smtp instead of mail().

CiviCRM version 5.13.4, WordPress version 5.2.4 & CiviRules version 2.10

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